APRIL 20, I 900.]

THE DESIGN OF ROTARY CONVERTERS.

By H. F. PARSHALL, M. INsT. C.E. , H. M. HoBART.

(Continued jr01n page 244.)

and

RuNNI~G CoNDITION FOR RoTARY CoNVERTERS.

E N G I N E E RI N G.

current input, then the volt-amperes input will be equal to the sum of the no-load loss.

No-Load Losses. Core and stray losses at normal voltage= 20,000 watts Friction and collector C2R losses . . . = 8, 000 " Shunt field self excitation = 6.4 x 500 = 3,200 ,

Total no-load losses ... Watts per phase ... . .. "Y" voltage = ~O ...

.../:f

... ...

. .. = 31,200 "

. .. = 10,400 ,,

... = 180 volts

499

amperes entering a collecting ring corresponds to 1000 = 580 amperes in the armature conductor. "/'3

R esistance of armature bet ween commutator brushes has been given as .005 ohm at 60 deg. Cent. =R(page 197 of ENGINEERING for F ebruary 9, 1900).

Then the resistance of one branch (i .e., one aide of the A) will be 1.33 R = .0067 ohm.*

In each branch there will be a C2R loss of 5802

PHASE CHARACTERISTICS.

THE conditions relating to starting rotary con­verters have been considered in a previous article (see ENGINERING for February 23, 1900, page 241). After being finally brought to synchronous speed, there remain various adjustments requisite to secure the most efficient performance, and to adapt them to best fulfil the special requirements.

Phase Oharacte>·istic.-The term phase charac­eristic is generally applied to a curve plotted with

•

Fig. 49. of 125Kw. 35 ~~. 116Vol..ti Three Pha.sfl Rotary Corwerw:

Power Fad:nrirv terms uf .Amper0 Turn6 per FiRliL SpooL.

11.9. 46. NO LOAD PHASE CHARACTERISTICS. fmuJCOJl..() .Al.· ·1 'nh:ng WrretU/ Pot;.enti,aL of 7 5VOl.ts betweol/ rings

"'

(J

-8

I]

-6

'5

'4

·3

:2

4

0

of 8001fw. 2 5 ~cle~ 500 VoLts ThruPha...se Rcw.ry Corwerter .

P(]Wtr Fa.ctor ill/ t:.o7Tu> of f'u!J.dJ Ex.~ •

.

•

J I \

/ " ' ~ ~ ....

' ~ ~

·v

• 9 ~-110~ f41 JJ. u 0 ::;- ...

I"" •u

v.(j :/~ .. !))'

/~·J_,O V -ltt.

•

'

•

•

·1

12

1-n ~ cor!~?' " v. fi:~ ~· ..,...... ......

-ton. .... /(;;ft\1'

.... ~ ~

V" f(ol1" ~ .......... r-.... ~~ .

J 1\

V \ J ' [\

V \ V " V

~ ~ ........ .......

r--.... loo... g...

1 z 3 4 Amperes

~ 6 7 8 9 10 11 Fteld Excitation. I ~ 600 . 1000 16()f) 2 000 Z600 8000 8500

. ' Fifj. 47. NO LOAD PHASE CHARACTERISTICS. ($~1/1) ---· . · . : Ampere turns per Field Spool.

J qf 9001Iw. 25 ~t:l£8. 50fWoU:s. I Three Pluut!~Rot.o..Ty Corwerter. • I -1 I I I 1 I · [ I I I I. • Power Fa.aur t7v tums uf AJ.were.s r;er CoUeccor Ruw .

Jis. 48.

• . -

PHASE CHARACTERISTICS

of 1251fw. 30{#~115Volv ThreeP/uuelloto.ry Cmwerter.

Constant~ .A furren.b Potential; of . 1SVOla betweelt/riiLf]s. ,

, rT-rr-TI~Jr~rT-r~~-.~~~-·_,

.

\

~

\

"' ........ ..........

I •J ·Z • • ~

. Power Factor

field excitation (preferably expressed in ampere­turns per. field spool), for abscissre, and with amperes mput per collector ring, as ordinates. Such a curve ~ad been given for no load in Fig. 32, on page 197, of ENGINEERING, for F ebruary 9 1900, and from an examination of it one learns that' ~t normal v~lt.'l.~e between collector rings (310 volt; 1~ ~he macbme m question), and a field excitation o A amperes (6800 ampere-turns per pole) there was required only about 80 amperes per phase to run .t~e rotar~ .converter unloaded. This is the conditio~ of. mtmmum current input ; with weaker fiel~ e~C1t.at10n the current laas and with stronaer ~Xcitat1on it l.eads, in both ca.~~s increasing rapidly m amount With the varying field excitation The curve shows that with no field excitation, the cur­re~t .Per phase increases to about 2100 amperes 8\hltt ~so reaches approximately this same ''alu~ Wl wtce the normal field excitation. ~ If the cun-ent is in phase at the point of minimum

.., We reproduc th' bl k h · save the read the 18 oc on t e next page m order to er e trouble of referring back.

Amperes per phase (i e., enter­ing each collector ring) = 10.400

180 .. · .. . .. . = f>8 am pares

Hence we have an unac-counted-for balance of 80 -58 .. . . .. ... . .. = 22 ,

0

(SJfi CJ

This is due partly to a difference in the wave forms of the generator and the rotary, but chiefly to so-called'' surgina " effects, and will be a varying value de­pending upon the motive power drlving the generating alternator, and upon the tnethods employed to limit the effect. It will be considered in a subsequent para­graph.

~egl~cting the ''surging" effect, for a given field excttatwn, .the power factor of the incoming current may be. estuna.ted. Thus the curve of Fig. 32 shows that w1th t~e .excitation of 3. 2 amperes (half the normal ex01tatwn) there is an incoming current of 1000 amperes per phase. One thousand

•

•

•

400 1000 16QO 21JOO 2600 8000 8600 tUJOO 46(}0

•• J .. Ampere Turns per Fi'eld Spool.

x . 0067 = 2260 watts, and therefore a total arma­ture C2R of 3 x 2250 =6750 watts. The field exci-

* Proof that, if R = armature resistance between eo m_ mutator brushes, then 1.33 R = resistance of one side of the A.

Take the case of the present rotary. It has 12 poles,

soo ta.tion with regulating rheostat losses will be one­half its former value, i .e., 1650 watts. The core loss and friction remain substantially as before, but the collector C2R loss is increased by 600 watts.

Swnnutry.

Armature CZR . .. .. . ... Field self.excitation ... . .. Core and stray losse~ . . . . .. Friction and collector C2R lo~ses

Total of losses . . . . .. Total per phase . .. . . . . .. Volt amperes input phase= 580 x

= 180,00 Hence power factor = 12 3 = .068

180

...

... ... ...

. .. • • •

310

\Va.tts. 6,750 1,650

20,000 8,500

36,900 12,300

Similar calculations for other values of the field excitation, give data for plotting other phase characteristic curves for n o load, that is, for no output from the commutator. Thus in

2200

00 i\

18llll \ • ~0()

/4(}0

120/}

80

'0

4()0

zoo

~

ObservetL . PHASE CHARACTERISTIC urv 800 Kw. 26 Cgt:Us 600 Vol.td

Thru Pluue Rotary Corwerter .

Pr!J.32.

i

\ f_ 1\ / ' V \ / ~ J ' 1/

1\. )

\ V IV

I I

0 I 2 3 4 .S 6 1 8 9 10 11 12

(51428) Amperes in Field

~ •

250

Fig. 46 the power factor is plotted in terms of t he field excitation; and in Fig. 47 in terms of the amperes input per collector ring. These curves have all corresponded to no load, but other phase characteristic curves may be obtained for various conditions of load.

In Fig. 48 are given phase characteristic curves at no load, half load, and full load for a 126-kilowatt rotary converter. It will be obser ved that the phase characteristic curves with load possess the same general features, as the curve for no load, though less accentuated.

In Fig. 49 these curves are transformed into three others in which the power factors are plotted in terms of the field excitation ; and in Fig. 50 the power factors are plotted in terms of the amperes input per collector ring.

F igs. 46, 48. and 49 show the importance, especially with light loads, of careful adjustment of the excitation. The power factor falls off very rapidly indeed with variations of the field excita­tion from the normal value. However, with load,

and a multiple-circuit single winding. Therefore there are 12 paths through the armature from the positive to the negative brushes. There are 576 total turns on the armature. Hence each of the 12 J>aths has 48 turn R = the resistance of the 12 paths m parallel . ·. 12 R = resistance of one path of 48 turns. But between two col· lector rings the 576 total turns are divided into three groups of 192 turns each. One side of the ~ is made up of one such group arranged in six parallel paths of ]:2

= 32 turns each; 32 turns in series will have a resistance of

32 - X 12 R = 8 R, 48

E N G I N E E R I N G.

the variations are comparatively moderate, and field regulation can then advantageously be employed as a means of phase control ; and through the inter­mediation of line and armature inductances, some­times aided by auxiliary inductances employed for the express purpose, a considerable working range of voltage at the commutator of the rotary con­vertAr, may be obtained .

This brief description of the phase characteristic curves, permits of now explaining, in a rough, prac­tical way, what causes the current to lag or lead with varying field excitation, and also what controls and determines the extent by which it sha.ll lag or lead. Suppose a generator, say by hand regula­tion of the field excitation, is made to furni h 310

[APRIL 20, 1900.

ay, to one·half, then, since there is t i11 the same terminal voltage, it follows that there must also be the same flux M impelled through the same maa. netic circuit. The remaining part of the required magnetomoti ve force ha..q, therefore, to be our,ht for elsewhere. It is, in fact, furnished by a l~g­g1ng armature current which then flows into the collector rings. This component does no work hence it is 90 deg. out of phase. The resultant current is composed of the energy component which overcomes the losse , and this wattle current. Thus, in the first analysis made in this article of the phase characteristic curve of Fig. 32, it was found that reducing the field excitation from 6.4 amperes (corresponding to unity power factor) to 3.2 am-

~~~(o~r~u;~i.anb_~-~' J!IIJ-~. ~ ,~n · ~· n. ~';ru_· ~~ fii~,'l:,o,~ur!!•·~:.~~~.J~o~tOt~· n~' n~·, l~'!!.!uf:417~6]~~lJ.6~~~~··~· 'eert/~(Jr~~n·{j~·~C'-+-+-t-t~'~~~~~~l i--+--+-

120v ""'~/Q .,':"""t-+-+--f

1000~~~~~~~~+-r-r-r-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-~~-4-+~~

tJ ., ·5

(~ll) Power Foetor

.51. ~1!/ R(ltary Com.1crter.

J • q{' ru;al..t:a.nb arrrr.a.b.n-f!/ I\

I \ TU!QJ-mot::Ure- {urc,e, over ~ '

•nh1~e, sur~. . -" ' ' / \

V \ I 1\

\ V -\

\ •

),

\ I ' If

• I

A A @~ C ~If] C C C 8 8 8 8 8 8 A A A C 8 8 @ 8 A A~ A CC CC CC

-1 - 1 - 1 - 1 - I ·~ •;S • ·5 · ·5 · ·.5 · ·5 ~..s +..S •-5 •'6 .-!I · ·5 - 1 -1 -1 -1 - 1 .. _, ... 5 -..s -• .5 .. 6 ·1 +1 •1 .. , ., ·1 -:.S -.s -.s -.6

_ _, -~ - .J · S ,.

-15 - 1!J -1~ -15 - 15 0 0 0 +1'5 +1 5 +15 -+1·5 +1·.5 '

• 1·5 0 0 0 -16 -7~ -1~ -1'5 - 1'5 l:l

:i-lru; cu.rN!:J1,.() v~ 1.7t/ ~ ~er COTit.d;t;~'JT'"S. • ,, . , ., J.' lOWer .•

11U1~ Uv'T"f!J'"LV va..b.J..es per pau- er Curub.J..ctors.

volts, under all conditions of load and phase, to the · peres, increased the input from 80 a!Dperes per col­collector rings of a rotary converter. (Assuming lector ring to 1000 amperes per rmg. The mag­t he rotary converter to be of very small capacity netising component of this 1000 amperes was r~latively to tha~ of the generator, these variations !0002 _ 802 and hence scarcely differed for 1000 wil~ not. mate~lly affec~ the generator voltage, ' 1000 _ whiCh wtll rematn approximately constant.) I amperes There are, therefore - = o 0 am-

It has been shown that there will be sub- · ' J3 and six paths in parallel will have a resistance of 8

: stantially 500 volts at the commutator when there . 580 = 1.33 R, and this equals the resistance of one side of the are 310 volts between collector rings. This is peres per s1de of the delta., or 6 = 97 amperes A. Q. E. D. . . . . . fairly independent ofh t

3he

0field

1 excitation. But per armature conductor. This, assuming a ine

Any difficulties in understandmg thts subdivtsion of figuring from either t e 1 \'O ts at t he collector 97 J 13 the winding into groups and parallel paths may be re- rings, or the 500 volts at the commutator, the re- wave of incoming current, is x 2 = . moved by a study of the winding ~ia¥~m for the mul- suit arrived at is that there is a magnetic flux M maximum amperes. A current of 6.4 amperes m tiple-circuit single winding shown 10 Ig. 8 on pa.s-e 449 per pole-piece, linked with the armature winding the field corresponded to a magnetomotive force of of EsGINEERING for October 13, 1899. Ana.log~Jus myes- turns. When the field excitation is such as to 5800 ampere-turns. This, with 3.2 amperes was tiua.tions of two·circuit singl~ wi!ldings. and ~f mu~t1p~e 900 th · · tg QOOO w'i'ndings of both the two·CJ.rcUlt and multtple._ctrcutt afford the requsite magnetomoti~e force for impel- reduced to 2 ampere-turns. e ,·emm~u' .. tvpe, will yield the sa.me result, i.e .• that the res18t&nco ling this flux 1\f against the reluctance of the mag- ampere-turns per pole-piece bein~ su_pphed by tl2e of one side of the~ is equal to 1.33 R for three·phase netic circuit, there will be no current in the arma- lagging current in the armature wmdmg. The 1 -rotaries. For a.n exam~na~ion ~f these lat~r cases. one ture or rather only t he small amount necessary pole Brl"mature has 676 total turns, or 48 per pole-may make use of the wtndmg dtagram of Ft~s. 9 and 10 ' 'I h ' t d b h 1 d · b t th 48 turns per pole piece belong to on oages 449 and 45o of E.~c Jl\""EERING for October 13, to supp y t e. power rep resell: e . y .t e no- oa p1ece ; u ese -1

•93

. • lon es. But if the field exettat10n 1S weakened three different phases, hence there are 16 turns

APRIL 20, 1900.] E N G I N E E R I N G.

per pole-piece per phase. The maximum ampere­turns per phase are

t ion · which leads to the con clusion that i t is the location of this magnetomotive force in the arma­ture conductors themselves, which enables it, wit h from 10 to 25 per cen t . less magnit u.de, to ~eplace t he, in t his respect, less effectively s1t ua ted magnotomotive force of t he field spools, the flux

16 x 138 = 2200 ampere·turns.

In Figs. 51 and 52 are shown diagramma~ically, the arrangrment of the couductors of the d1fferent

Fig.S9. ~Phasf!/Rctwy Cmwercer. · ... · nh'

""'"" of t::lth r~ arrru:LI».rl?/

/ V "" '

m.agneto·mocive- furre (JVU dw -, ,nh1 8~. V "" / ~"-.. - .... V 1\ I

- V \ )_ I 1\

\ 1/ I

-··- - -

\ J \ V •

1-- ·

"' V I

~ / --- -

" V ~ / •

....... V

-- tJ <

'r£1 I ) )

~ ~ ~ ~ [£] [£] (£] [£] [fJ ~ !m @ rm !m @ ~ !A] 0] @ []

r= ~ If] ~ If] ~ c [f] [§] rm 8 !m !m 8 @ ~ ~ A lA c c B =

- ·BG1 - 86'1 -·86? - -861 - ·86? · ·BG1 ~·8fJ1 .. ·86'1 - ·867 • o(J6? · ·861 0 0 0 0 0 0 - -861 - 66'1 - -861 - 86'1 - '861 tr

-861 - 861 0 0 0 0 0 0 ·8~ · ·BG? • ..S6? • '66'1 ··86? .. 86'1 -861 - '861 -861 - -861 -·86'1 -.fJG'l 0 0 2<

- t?S - 1"18 - ·86'1 - -86? - BG? • ·86?~867 "T 867 • 7·78 • 1'l:J - 113 .. 861 • -86'1 -t 86'1 - 667 -·fJ6? ""8111 - 1-'lS - 1"18 - 1·'13 - -86? - 86? :c;f

·~ f:rtsta.nta:ruwu.s carrerw valn.es trV ~ upper ccnd».ctors. X , , ., ., ,. ., Wwe:T' ,

". 1141 ~. rurrenv vah..I..e6 per pair of' cunJ<lu'£arr.s. I

•

SOI

the centre about which the whole carriage can ?~cil­Iate. The bogie frame is just below tho grrder member which bears the l'a il, cu1 ved to that centre, and the gap between girder and frame-only 7 millimetres (0 .28 in. ) - is so small that t he wheel cannot jump from the rail, a~d thu~ the frame would be held tight by the guder 1f any part should break. A struct ure about 25 fti. above the street level in which nothing can fall on the line from the rolling stock, is, of course, muc~1 less endangered in tha t respect than an ordl­nary surface track. On the other hand, there are always mischievous persons of al~ ages wh.o cannot resist the tempta tion of trymg expen­ments and an elevated line is not inassail­able. ' The upper part of the hook is extended longitudinally, so that in case of an axle break­in()' the whole bo()'ie would fall through a small

0'

0 • f 11 height, and rest on the rails, pre~entmg a . a

phases in the armature slots of a three-ph~se rotary, and directl:y above, the corresponding curve of magnetomot1ve force due to the currents in the armature conductors. Fig. 51 represents the instant when these relative current values in the phases A, B, and C are, respecti·vely, 1, .5, and .6. In Fig. 52 these have become .867, 0, and .867. H ence it is, in Fig. 51, that one phase reaches the maximum value 1, and as there are six conductors per pole-piece p er phase, its maxi­mum magnetomot ive force may be r epresen ted by 6. But alt hough, in Fig. 51, the corresponding maximum value of the magnetomotive force of the three phases is 9, it becomes 10.4, one-t.welfth of a cycle later, at t he instant represent ed by Fig. 52. Hence in a t hree-phase rotary converter winding, the maximum magnetomotive force exerted by the armature conductors of all the phases, is, per pole-

set up from which latter, suffers diminution, magnet ic leakage, on the way to the armature.

(To be continued. )

of the carriage. The bogies c~nstst essent1~1ly of pressed steel, riveted hydrauhcally. In F1gs. 18 and 21, we see that the connection between bhe bogie and the carriage is effected by means of a cross-beam of pressed steel, fitt ing into a recess in the lower part of the bogie frame. Each cro.ss­beam is rigidly connected with steel pins wh10h move in a neck-bearing and a foot-step of the bogie frame. This novel method of connection avoids the applications of bolts, screws, or wedgee, and imparts great strength and safety t o the whole arrangement. E,·en if t he flanges should be shorn off, t he beam could not sink further than the lower part of the bogie frame which embraces it. This part cons ists of strong steel plates, flanged and riveted. The elastic connection between the body of the carriage and the ends of the cross-beam is similarly strong and secure, as the ends pass through openings in the longitudinal carriage girders. These upper girders have webs of 350 by 5 millimetres (13.8 in. by 0.2 in. ), and they are carried right round the r oof, tapering towards the extremities. They take up the compression and tension of t he coupling devices. The U-irons

by which embrace the carriage body are riveted to them. The steel plates of the carriage walls have a thickness of 1. 5 millimetres, and they are suit­ably edged and strengthened below the windows.

piece, I0.4 = 1. 73 t imes as great as the maximum 6

magnetomotive force per pole-piece per phase. Now, for the case under consideration ·(the 900-

kilowa.tt rotary), t he value of 2200 ampere- turns per pole-piece was found for the maximum mag­netomotive force per phase. Therefore the maxi­mum resultant armature r eaction for t.he three phases would be

1.73 x 2200 = 3800 ampere-turns per pole-piece.

But it is only in opposition to the flux at the very centre of the pole-face t hat t he armature magneto­motive force would exer b this strength. Approaching both sides, ib shades off towards zero, as may be seen from the curves of magnetomotive force distribut ion of Figs. 51 and 52, whereas the fi eld spool against which it reacts is linked with the entire pole-piece. In practice, these magnetomotive force curves would be smoothed out into something like sine curves. Hence we may take the average ma()'neto­motive force exerted over the whole pole-f:ce as

3800 about = = 2700 ampere - turns. This corrc-

"'2 spo.nds fairly 'Yell wit h t he 2900 ampere-turns by which fi eld exCitation was reduced.

At fu·st sight, it would appear that this checks wep enough for all practical purposes, but an analysts of the curves of many other rotary converters resulted in almost always finding that from 10 to 25 per cent. less magnetomoti ve force on the armature, suffices to replace the field excita -

•

THE LANGEN MONO-RAIL SUSPENDED RAILWAY AT ELBERFELD-BARMEN.

(CD'ncluded fnm~ page 439.) THE carriages (Figs. 15 to 21, on our t wo-page

plate), which were built by V an der Zypen and Char1ier, have a lengt h of 11.45 metres (37.5 ft. ) and a width of 2 metres (6. 5 ft .) and can accom­m.odate 50 passengers who enter and leave by two side doors, opening inward. Part of the wall opposite the doors and the end doors open out­ward, so that passengers may step from one car of a train into the other. If a train should stick on the track, the train following could be brought up, and the end platform, which is provided with guard raile, lowered so that the passengers could enter that train. If the still more un­likely case should happen that either the up or the down line should be blocked entirely, owing to failure of the current, the passengers would be able to move over to the opposite train on the other line. The current supply to the two lines is entirely separate, and a large battery of accumu­lators has been put up at the central s tation. The trains are to consis t of two carriages, but may be increased to four. The common car controller for all motors is in the first carriage, in the front com­partment on the right-hand side ; two controllers are not r equired, since the t rains always t ravel in the same direction. The levers of the hand-brakes and of the au tomat ic W estinghouse brake, as well as of circuit breakers, are to be found at bot h ends of each car, accessible to the guard, and, in cases of emer­gency, to the passengers. The compressed air is taken in at the termini under a pressure of 115lb. p er square inch. The five iron pipes, 11 metres (56 ft.) in leng th, and 4 in. in diameter, which serve as air cylinders, can be seen in Figs. 16 to 19. They run under the fl oor of the car and help to sup­port it.

Each car is suspended from two bogies, 8 metres (26 ft.) apart, each running on two wheels, 900 millimetres (35 in.) in diameter, driven by spur gear­ing from a 36 horse-power electric motor, fixed between the two wheels and projecting outward. The lower part of the hook-shaped bogie frame is adjustable. The round railheads in Fig. 21 form

Eight of t he U-irons already mentioned by the side of the lateral doors are strengthened by plates, and prevent also any shifting of the lower portion of the body with regard to the upper, owing to action of the buffers. The strength of the car depends entirely upon the mild steel, which has been used throughout; the wood serves only as a li ning.

The weight of a carriage with its full comple­ment of 50 passengers is estimated at 14 tons, made up as follows :

Two electric motors, with complete elec-. trical outfit .. . .. . .. . . .. . ..

Two bogies with buffers and cross beams Carriage body, with seats complete .. . Passengers .. . .. . ... .. . .. .

Lb.

6,743 3,960

12.903 7,700

That would signify a carriage weight, including everything, of 280 kilogrammes (618 lb.) per pas­senger. On elevated electric rail ways, we are informed, cars of the same capacity have so far not been made of a lighter weight than 20 tons, which would give an average dead load on the track of 400 kilogrammes per passenger. The small weight is, of course, a point of considerable impor tance. The s uper­structure weighs only 1140 kilogran1mes per metre (about 700 lb. per foot), although it satisfies t he regulations for the r ail way and bridge construc­t ion of the Prussian State. These figures corre­spond to the average distance of 30 metres (lOO ft.) bet ween two consecutive supports . As a compari­son with another elevated structure of r ecent date, we may r efer to the figuref; which wer e published by Ba.ltzer in the " Zeitschrift fiir I{lein bahnen," of 1897, on the electric elevated tramway of Berlin, built by Siemens and Halske. With spans of 16.5 metres, a litt le more than half of the 30 metres adopted at Elberfeld-Barmen, the iron structurE', not reckoning the rails, wE'ighs 1400 kilogrammes, and when the supports are placed 21 metres (70 ft.) apart, we have a load of 1800 kilogrammes p er metre, equivalent to 1200 lb. p er foot. We notice that any increase in the span at once augments the weight of the ordinary elevated structure considerably, and t hat the cost of the iron­work should be smaller in the case of an elevated railway wit h suspended cars than with ordinary

502

cars. The cost of the raw material is not decisive , of course. As regards cars and electrical outfi t the comparison will naturally be in favour of the ~rdi­nary t ramC<:'l-r which need not be substantially built. The Langen carriaaes are, however not complicated. and look certa.~ly very much si~pler than the Behr carriage of 1897 a.t T ervuren which ran on forty wheels, though on a very much cheaper trestle-framing. A direct com­parison i not pos ible, however , as the Tervuren track was single and not an elevated tructu re. The total building expenses for the loop track at Elberfeld will amount, it is stated by the Conti­nental Company for Electrical Enterprise, to about 35,000l. per kilometre (56,000l. per mile). That would be, it is added, about a third of the money sunk on the Berlin Electric Elevated line, and from four to eleven times less than what has been spent on the L ondon suburban lines-what­ever that may mean. '\Ve will not trouble to check t hese figures, as they are only rough estimates ; we shall learn more about these features in due time, when the railway is really in working order. It is intended to run trains every t hree minutes ; but all that remains to be een .

After these general considerat ions we return to details. It has been mentioned that the two elec­tric motors of a. carriage are each of 36 horse­power. They ea~ be connected in the usual way, In parallel or senes. The current of 530 volts is taken up by a contact shoe, held by an inclined lever, pressed on by a spiral spring, marked in Fig. 10, page 441 rtnte. The contact rail is fixed to obliquely placed insulators. After ex­periments with copper wires and various rails, an ordinary iron rail conductor, with a round head, which the shoe embraces at all positions of the carriage, has been found to answer best. The arrangement is very much like that on our oldest London electric railway, only that the shoe rubs from below instead of from above. The advantage would be on the side of the Elberfeld arrangement. The carriages can be stopped in various ways. 'Ve have first the Westinghouse compressed-air brake; the shoes press on the top of the wheels, as can be seen in Fig. 20, and the valves are under the control of the engineer, or, rather, motor n1an. The same brake mechanism can be actuated by hand, both by the motor man and the guard. There are, further, the usual elec­trical means of stopping a car, either by reversing the current or by cutting the line current off, and allowing the motor to act as generator.

The transverse partitions in the carriages would probably be maintained, even if the distinction of first and second-class were abandoned, or if the different cla ses were given separate carriages, as they facilitate the emptying and filling of the car­riages. In long cars people often cannot make up their minds which way out they are to favour. We mentioned that each carriage accommodate 50 pas­sengers, 34 of whom may be seated. rdinary trains will consist of one or t wo cars. The platforms will, however, be constructed for easy extension to permit of trains of four cars being run. As each carriage is provided with its own motors, the length of the train should not influence its speed. The two or more cars of a t rain are rigidly coupled to one another by means of rods, indicated in Fig. 16. With trains of four carriages 6000 persons could be despatched per hour in either direction, but so heavy a traffic is hardly expected.

The rails are of the Haarmann type, 4! in. high, 'vith a rounded head 2.2 in. wide, with lap joints. They rest on plates and wit h an intermediate layer of felting on the member t of the upper horizontal girder. This girder has the form of an I , and its lower surface is curved like t he part of the hook frame below it ; the rail head is the centre of the curve, and the swing of the carriage is limited by projections on the bogie frame. The amplitude of the oscillation c1nnot exceed 15 deg. , reckoned on either side of the normal.

The t rack is divided into automatic block sections, which permit of sending trains at intervals of two minutes. There are no signals along the line apart from the signals at the stations, so that the driver has not to look out for anything but the approach­ing station. He starts when his station signal marks the lin~ clear. His own carriage then blocks t hat signal, while it gives " line clear" to t he preceding block. If any signal should fail to respond, traffic is delayed, but not endangered. The staff can change a green into a red signal, but not 'lJice ve,·sd. So far f'S the actual experien€e permits to ~ udge, the cur•

•

E N G I N E E R I N G.

rent consumption does not appear to be much greater on the elevated train~, with t heir fast ser­vice, than on the surface tram cars, which do not attain hal~ their pccd. Increased traffic may alter that .relatwn, but the elevated track will always rema1n much cleaner a.nd in bet ter condition than the surface rails, exposed to all the s treet mud and other heavy street t raffic. The platforms can be arranged on either side of the track, or between the up and down rails. The latter arrange­ment would be simpler in certain respects, and reduce the number of attendants. But it would either require a much wider track or would call for curves at each station, both undesirable features ; hence it has not been adopted.

The stations are tastefully built in iron and glass. The decorations were designed by Archi­tect Mohring, of Borlin. An easy stairway leads up to the platform. The lower edge of the carriage is 4.5 metre (about 15 ft.) above the road pavement. In ordinary elevated railroads, the lower edge of the permanent way is at about that height, and the platforms are at a higher level, as the height of the wheels and the thickne of the

Fi1J .2:l.

..

•

(APRIL 20, Igoo.

main track, a climbing switch, a doubly _nclined plane, has t o bo applied ~o allow the wheel flanges to get . clear of the r ra1ls. . uch switches are further m use at the ~oologtcnl Garden tation which forms the terminu for many travellers: Lest the poorly filled car ' should have to make a u~elessly l?ng jo~rney, a return arc has been pro­v.tde~, which 1s 11lu tratcd in !ig. 23. The loop hne 1s lowered beneath the mmn track . utliciently to allow the electric motors to clear the track above. I t will be interesting to see how this arrangemen t will work.

A few words on . other types of Langen railways. Elevated .town railways must necessarily be costly undertakmgs, unless we start with the rail way and dot the house along it afterwards. For aood trans­p~rt, the st~~cture ca,n be simplified to ~ery econo­m~ca.l cond1t10ns. } ... xperiment. have been made w1th field and mountain line , supported by posts of wood or iron, joined to form A -frames, placed 20 ft. or 25 ft. apart. Hooks, pivoted above at the apex of t he frame, are riveted to a hori­zontal ~ird~r whi~h forn;ts the permanent way, and wh1eh 1s prov1ded With one rail above and

• •

·-~ ·----• .. 5 ~ • - . • - --·--· ·- ~

• S!

•

-.. •

( • •

-(SI8Z C)

structure intervenes. Here, then, t he elevated suspended rail way again scores over the ordinary elevated railroad. At New York the platform level varies considerably. In .Berlin the elevated platforms are stated to be 25 ft. above the street level ; that would make a difference of 10 ft. in the stairways, which is well worth mentioning. In Fig . 22 we find a diagram of the arrangements of the terminus at Vohwinkel. The site adjoins the tate Rail­way, and the shed is common to the new elevated and the old electric tramway line, which is marked in dotted curves. The street is the high road between Diisseldorf and Elberfeld . The shed i a building of two storeys. The lower torey accommo­dates the street cars, and contains, further, t he repair shops for both services. Carriages of the elevated line are raised and lowered by means of lifts. The eight rails which we notice in the shed are con­nected in two groups by means of the switches a , b and c, cl, and the groups further by t he semi­circular track a c. The shunting of the carriages is very simple. As a rule they come from Barmen and E lberfeld up to j, and return through the arc rail f h, which is a curve of 8 metres radius, de­scribing their loop without entering the shed. At night the cars have to be distributed on the diffe­rent rails in t he shed. This is done with t he aid of the switches e and j, by which the cars enter, and g and h, by which they leave. If either switches should be out of order, the traffic can be worked by the others.

When a car is to Pass from a sidinJ.l on to the w

•

• •

I

To Vo · • •

• -

one below. The two rails are in the same ver­tical plane. The car suspension is effected by means of &. C -shaped piece, fixed to the motor truck, which has two wheels above, and to a small t ruck with two wheels below. These latter wheels are added for the purpose of increasing the adhesion on gradients. The experimental track men­tioned is carried in a curve over marshy ground, where the wooden frames stand in water, and leads up a hill with a gradient of 1 in 6. n this steep gradient a special electric motor car .i e~ployed ; each of the cars grip the two ratls wtth four wheels above and four wheel below. The A-frames can be light, and if two con ecutive frames are braced at intervals of about 200 yards, no further stiffening will be required.

Steep gradients can also be overcome by ma~­ina the lower rail a rack. Such a scheme IS

being worked out, not only for a light railway, but for a passenger extension line from Elberfeld to one of the neighbouring hills which th.e people frequent. 'Vith the pendulum suspe~s10n., the car hooks would always hang vertical m sptte of the varying gradient ; but to keep the cars them­selves always horizontal, as is inten~ed would, we hould think, in\'olve a very complicated suspen· • ston gear. . The last type of uspended railway wluch t~e

company is developing, the suspended rope ra.il­way, will admittedly profit least from the ~pe.ctal adYantages of the sytstem. It is worth mentiOniDgt h o ever, since " line of this t;ype i~ unrler construc

4

APRIL 20, 1900.] • tion at Loschwitz, near Dresden. Several streets and a compar~tivel~ deep valley ~ave to be c:o3sed ; and the line IS to rise 80 metres I~ 250 metros. A rope railway offers the only solutLOn of sue~ a p~o­blem as the building of a surface road w1th via­d 0~ carried over valuable house and garden ~op~rty and public ground, would swell th~ cost

~ut of all proportions. A double track will be adopted. .

Before concluding, we rt?Ight refer to one of the defects charged against thlS and al~ other eleva~ed railways. It is contended that~ d~.rect connect10n between the elevate~ lines whiCh fall ';lnder the category of street raiL ways, and the ordmary sur­face tramway is impossible. The correctness of that charO'e cannot be denied. Suspended cars can manifestly not be r endered amphibious, suitab~e for life in air and on surface tracks, unless we .fit them both with gills and lungs, so to. say:-with motors and wheels above and belm~ likewise, or with special tracks, at any rate, on which they could be lowered. But the objection is hard~y worth refuting. We do not rememb~r many Instances where an elevated track passes Into a surface road line and do not see any necessity for troubling abo~t this weak point of the suspended car system for the present.

\Ve conclude with our best wishes for the success of the Elberfeld suspended railway. M~ch in­genuity, time, and money hav~ been, and 'Yill hav.e to be, spent on this undertakmg, from which ~ngi­neers whatever be the measure of success attained, can ocly learn . 'W_e. in ~ondon,. and t~e inhabi­tants of the great cities with us, will cerbunly watch with sympathy and interest the development of any attempt to deal, on new lines, with the great problems of rapid urban t raffic.

1YIODERN FIELD ARTILLERY. (Oontilnued f'rom page 469.)

4.7-lN. BREECH-LOADING FIELD E QUIPl\IENT.

W~; conclude our series of the Field Artillery of Messrs. Vickers, Sons, and Maxim, Limited, by giv­ing, on pages ?04 and 50?, view:s of. their 4. 7 -in. gun carriaO'e and limber, designed ID VIew of the neces­sity e:tablished during the South African War for a larger weapon than our 15:p~under equi~m~nt. The gun itse~f is of steel, co~slStmg ~f ~our d1s~1nct parts, includmg the breech nng, and It IS 25 calibres long in the bore; the total length from the breech face to the mm:zle being 10ft. 5t in. The gun is constructed with an outer tube extending the whole length of the gun, shrunk on an inner tube or liner, and held in posit ion by a bush, screwed into the breech end of the outer tube, and in this the breech plug of the mechanism is screwed. A steel jacket is shrunk on t he outer tube, and extends over the chamber and that portion of the bore where the highest pressures are experienced, and is connected to the outer tube by shoulders and by the breech ring. On the underside of the breech ring are two projections, to which the piston­rods of the hydraulic buffers are attached.

The breech mechanism is similar to that of the 12-pounder quick-firing field gun, illustrated on page 411 ante, excepting only the firing gear, which in this case is achieved by percussion instead of by friction. The principal particulars and weights are given in the subjoined Table :

Particulars and Weights of 4.7-b t. Breech-Loading Gun, Carriage und Limber.

Weight of Projectile . .. .. . . . . 45 lb. Diameter of bore .. . . .. .. . 4. 724 in. Length of bore .. . .. . . . . . . . 118.1 in. Total length of gun ... . .. ... 125.47 in. Length of chamber ... ... ... 17.5 in. Weight of charge ... ... .. . 4.5lb. Muzzle velocitY. .. . .. . . . . 1800 ft. per sec Length of recoil of gun in cradle ... 15 in. Diameter of wheels . . . . . . . . . 60 , , Track of wheels .. . . . . . .. 62 , Angle of elevation . .. . .. . .. 16 deg.

, depression . .. .. . . . . 7 , Angle of tratning .. . . .. . .. 8 , Hetght of axis of gun . . . .. .. . 42 in.

Weight of limber and 22 rounds of ammunition in carriers ... ... w . h f .

". e1g t o carnage . .. . .. Weight of gun and mechanism ...

Cwt.

25 21~ 30

Total .. . . .. . . . . .. .. . 76~

'fl:" Field Carl'iage (Figs. 81, 82, and 83).- The carriage consists mai11ly of the following parts :

(1) T1·"i1• with wheels• aNle, anfl aooket fo1·

•

E N G I N E E R I N G.

crosshoads. (2) Orosshen.d, \yith tho elo~ating and t raining goar. (3) Oraclle, w1th hydrauhc buffer s, running-out sp,·ings, and sights. .

The t rail which is const ructed w1th steel plates, strengthen~d by transoms, is fitted with o. shoo, a.nd an eye for limbering up.

The handspike is hinged to the trail, so as to be folded close without disconnecting, when not in use. The axle is constructed of steel, and is in two parts, each part being securely bolted to the s ide plates of the t rail. Additional rigidity is insured by brackets of steel plate, bolted to the trail and to the axle. Shoe brakes and chains are carried on t he trail in the usual manner. A socket for the cross­head is bolted between the trail plates by large flanges. The centre of the socket is a. small d~stance in front of the centre of the axle, so as to give the required preponderance at the trail eye. A short training rack is fitted to the r ear of the socket.

The crosshead consists of a steel V piece, with ·pivot-stem. The stem fits into the socket on the trail, the lower end resting on a. ball-bearing in the bottom of the socket. In the arms of the V piece are formed trunnion bearings, fitted with cap squares of the usual pattern. The front end of the cross­head is ' ' clipped" down to the socket by clips. A training worm, suitably mounted at the r ear of the crosshead, engages in a short rack on the socket ; 8 deg., i .e., 4 deg. on either side, are allowed for training. A side bar fitted to the left side of the crosshead projects r earward, and carries the elevating and training hand wheels. The elevating gear is actuated by a hand wheel, mounted to r evolve in a horizontal plane, and transmits the motion through wormwheel gearing to an elevating arc mounted on the cradle. The training gear is actuated by a handwheel, mounted to revolve in a plane oblique to the axis of the gun, and by means of spindle and bevel wheels t ransmits motion to the worm carried on the crosshead.

The cradle is a. bronze casting provided with trunnions, by which it is pivoted in bearings in the crosshead. The gun recoils in the upper part of the cradle. The lower part is bored at the r ear for two hydraulic buffers, and in the buffers are con­tained the running-out springs . A tank formed between the buffers, and in constant communica­tion with them, contains sufficient liquid to keep them always full. Each buffer is provided with a long controlling ram, to gradually bring the gun to rest when running out. The buffer pistons are connected to the gun in the usual manner, and the buffer has a. liner, in which are formed the p orts of varying section, so as to give an approximately uniform pressure during recoil. A boss is formed n ear the rear part of the left-hand side of the cradle; in this boss is socketed the rear sight. The f•)re sight is carried on a steel bar, easily detachable fr01n the cradle when necessary.

The carriage allows for a length of recoil of 15 in., elevation 16 deg., depression 7 deg. The crosshead and socket are so arranged that the whole may be quickly and easily removed from the carriage, and mounted on a pedestal if desired.

The Limbe1· (Figs. 84 and 85). - The limber, which is constructed to carry 22 rounds of ammunition, consists of framework, ammunition b ox, limber hook, wheels, axle, and pole. The frame is made of fianged steel plates, connected by cross-stays and tie-rods, and is provided with flanged collars, through w hi eh the axle passes. To the front part of the frame is attached a platform and a footboard, raised to a suitable height on wooden chocks . The inner flanged plates carry at their rear end the limber hook, fitted with hard steel b earing-piece, and at their front end a forging through which the pole po.sses. The axle is of weldless steel tube, with arms rivetted and brazed in. The ammunition box, which is composed mainly of wood and strengthened where necessary with steel bands, carries 22 shells in separate compartments, artd has two compartments, each holding 11 cartridges, two draw ers for fuses in tins, and two trays for small spares. The door opens to the rear in two halves, the upper half turning upwards and resting on top of box, and the lower half turning downwards and resting in horizontal position, partly on limber hook and partly on quadrants at sides provided with s tops. The pole is of ash, fitted at the rear end with bra.ndling iron and strengthening strips, and at front end with crossbar and draught pole chains.

.A ntmtt.nition Wagon (Figs. 86 and 87). --The ammunition wagon is constructed on similar lines to the limber ; but the "two inner flanged ~;>lates" of Hmbe1· ate in the wagon l'eplaeed

-by a pole or perch, made from steel p~ate bent to a box form, and having fixed at Its . front end an eye to suit the hook of a second hmber similar to that used with the gun ; the rear end of this perch is built into nnd forms part of the framework. The internal arrangement of the am­munition box differs from that of the limber by being arranged to take 24 shell~ and a like ~urn her of cartridges and fuses; room IS also provided for one tray of small stores. A t ravelling drag shoe and chain are provided with the wagon; when ~ot in use this is carried on the top of the perch, being secured there by two small steel receiving pieces n.nd a strap. The wheels, axle, and the boxes at the r ear under ammunition box, are of th e same pattern as those on the limber.

(To be continued.)

THE INSTITUTION OF NA·v AL ARCHITECTS.

(Continued from page 476.) IN our two previous issues we gave a report of

the recent spring meeting of the Institution of Naval Architects, bringing the account up to the conclusion of the discussion upon Mr. Sandison's paper on '' The Oorvette ' General Banquedano."' We now conclude our account of the meeting.

U NIFORl\IITY OF TuRNING MoMENTS.

The last paper, taken on Thursday, April 5, was by Dr. L orenz, and was on "The Uniformity of Turning Moments of Marine Engines." This paper we print in full in our present issue, on page 529. As was stated in the discussion by more than one speaker, the paper was somewhat concise in its form, but this could by no 1neans be said of the dis­cussion. The subject is one of considerable im­portance, and is complementary, or rather a part of, that which formed the chief feature of this year's meeting, viz., the vibrations of engines. The contributions to the discussion, especially that made by Professor Dalby, were exceedingly valu­able, and we are glad to be able to give them at some length.

Professor Dalby, in opening the discussion, said that the somewhat terse form in which Professor IJorenz had cast his paper might possibly prevent many members present from at once appreciating the extreme elegance of the mathematical method that had been employed to gain a. working rule, the value of which would be instantly recognised. The equation from which the result was developed was one in which the twisting moment on the crank­shaft, due to a single cylinder, was expressed by a. ].,ourier Series in a series of sines and cosines plus a constant term. The fundamental importance of this mathematical form might be gathered fron1 the following quotation from Thomson and Tait's " N atura.l Philosophy :" " Not only is it (the Fourier Series) one of the most beautiful results of n1odern analysis, but it may be said to furnish an in­dispensable instrument in the treatment of nearly every recondite question in modern physics." After reading the proof of Professor Lorenz's paper, Professor Dalby analysed a crank-effort curve into a Fourier Series, and at the suggestion of Mr. Holmes he had ventured to bring both the curve and t he instrument before the n1eeting. The har­monic analyser, which he exhibited, was an instru­ment designed by Professor Henrici, and formed part of the apparatus of the City and Guilds Technical College, Finsbury. It was used ~ome­what in the manner of a planimeter, a tracing point being guided round the curve to be analysed, drawn on a base 36 in. long. A pair of coefficients of the sine and cosine functions were read off· the particular angle they referred to-</>, 2 4>, and 3 <I>

&c.-depending upon a change wheel in the instru: ment. Change wheels were provided to give the coefficients of t~1e sine and cosines up to 6 <P; so that the coefficients up to 12 terms miaht be determined. o

The curve, No. 1, Fig. 6, which we reproduce on page 506, was a crank-effort curve of an actual engine. The first tenn in the series A0 is the average height of the curve, in this case 8.2. This is to be d~termined by a plani~eter. Applying the harmonic analyser, two readings are obtained for 2 t/J, viz., 4. 8, from the sine roller and - 5. 7 from the cosine roller. A1 the coefficient of sine 2 4> = 4.8, and B1 the coefficient of cos 2 4> = - 5. 7. ~he thin curv~, .~ o. 2, represen.ting 4. 8 sine 2 ~' 1s set out bf d1v1dmg the base 1nto 15 deg. inter.1

•

•

\ Fig.81.

•

. • • ...

•

VICKERS' 4.7-IN. QUICK-FIRING FIELD GUN AND CARRIAGE . C 0 N S T RUC T E D B Y ME SS R S. V I C K E R S, S 0 N S, AND M A X I M, LIMITED, A T TH E I R E R IT H vV 0 R K S, K RN T.

(F(Yr Description, see Page 503.)

•

•

,..~, , . ' ' _: . ~n , ......... ""' ·r -------. :--....... -A::~:..,---cl ---- --·

•

- -. 7'! 0 £nt £ SSIOH

ScaLe :L tll-111"

Fig .8 2.

·---- . ----• ...

•

•

•

,

•

0

0

-

of _:I; :se:-. t or' la o o o 11 F 1 o o o

---

' •

-. .J - ..,

----

TONS.aw"IS qi'S. GUN,MECHANISM,SIGHTS

1AND CARRIAGE INCLUDING STORES . 2 . 11 . 2

LIMBER,WITH ·22 ROUNDS , AND STORES . I . S . 0 FIRST TEA141 .- S . 16 . 2 .

LIMBER WITH 22 ROUNDS, ANO STORES . I . 5 . 0 . AMMUNITION WAGON WITH 24 ROUNOS , ANO STORES . 1 . 5 . 8 .

SECOND TEA M.- 2 . ID. } ...:.

ooo

0 0 0 0 0 'O 0 ... 0 , , ....... '

11 • • • • • • • • ,.. • --~------ \

i ' : ----::=-::::r...--,· I ---'"----- I ' -------- ' . -''"'-··' () ()

---- _ __,.._1·---0 0 0 \0 0 0

• .J ·t:l] , __ ;. t

0 ~~~

•

•

(63JU.)

•

Ul 0 ~

trJ z () ..........

z t'Tj

t'Tj

Id ..........

z () •

I 1

~ '"d ~ -~ IV 0 ... -\0

8 •

•

A PRtL 20, i 900· J E N G I N E E R I N G. • •

4.7-IN. QUICK-FIRING FIELD GUN EQUIPMENT. I

MAXI~·• LI~ ·•ITED A'I' TH••'IR ~RITH WORKS, KENT. CON ' 'l'RUUT~D HY 1\1E~SRS. VICKER. ', ~ON~, AND J."J.' J.u ~ , .cJ

-·------. (For Description, see Page 503.) ,... .... •

I I • I • I I \ \ •

/

I

I •

\

Fie· 84 .

.Ftg.86 .

---

JUG.O. • -

FifJ.83.

vals, taking the values of sin 15 deg. and sin 30 deg. from the Table of sines, multiplying these by 4.8 in each case, and Eetting the products up as

•

•

•

S"'~ 7 ... . I tJv I

~.i4''

•

•

• • • •

•

If. CI.RTRIDG£S IN

CANVAS CARTOUCH£$

I

SPAReS.

.

If CARTRIDGES IN

CAHYiiS CARTOIJCHES -I

I I

I I

I I

'.2' ~~ "'------·--- 5· Jj --------·-----·-------------~ ~· --------- . •

Fig. 87. -- • •

• • ·'- ..... Jtt., . ,. , .. ,,. ·- .

. -·-='-.._ .... _.. ... - ,

t

•

I I

• I · ~ • • • •

'~ -~ ~ • l • •

I I • I I

I I I I • I

' I I

•

-'

. . :- . . I

~-·- -------------------s:z· l't'-w(, ------.::.~--------------- -~

'J • •

•

•

ordinates from the corresponding points in the base. The cosine curve, No. 3, is set out in a similar way. Ha,ring drawn these, the ordinates to the two

curves are added together, and to the mean height, from point to point along the base, obtaining a series of points through which the dotted curve No. 4 is traced. The speaker gave an instance when the crank angle is 105 deg., corresponding to the point A; these quantities were A C - AD + AB, giving Y = A E. He drew attention to the manner in which the shape of the dotted curve approached the shape of the real curve. It was only necessary to increase the number of terms to get as close an approximation as might be desired to the real curve. It was a feature essential to Professor Lorenz's paper, however, that terms above 2 </>had to be rejected. A comparison of curves N o. 4 and No. 1 would show to what extent equation No. 1 in Professor Lorenz's paper, enabled one to realise the actual conditions in any given case. Professor Lorenz had expressed the coefficients A 1 and B1 in terms of the mean crank effort, Tm. The assump­tion here was that the crank-effort curves were similar, and not, Professor Dalby thought, that the indicator diagrams were similar, as Professor Lorenz had stated. To obtain similar crank-effort curves, the net driving forces at the crankpin must be similar; and as these forces are obtained fr01n the indicator cards, after correcting for back pressure and inertia, they themselves could not be similar. Moreover, the inertia correction in each case was likely to be very different, because the recipro­cating masses would have been specially de­signed for balancing the engine. Assuming that the difference due to inertia corrections might be

•

$06

neglected, to get similar crank-effect curves cut­off would have to take place at the same frac­t~on of the stroke in each cylinder. This condi­tlOn alone would t heoretically fix the division of ~he comb~ned indicator diagram into high -pressure, Intermediate - pres~ure, and low- pressure parts. The method requued, further, that the division should also be made so that each part should corre­spond to a defini te amount of work, the amount being determined from the double-angled polygon. H ow far these two simultaneous conditions could be satisfied practically was an interesting question. In any case, the speaker said, Professor Lorenz's

.Fig. 6 .

--- x,·-.-- ' I \ )N9r~

/ '\. \ .t' . " \

.1 .,:'\N9l I . E

i . \

8 · 2 t---t-1~/-t--+-f---4--4--+8~\.\-+J\~M~' i:A~~N~H!_!:l£1!..!::.G~~.!.__j r/ '·\ / y

V ""-,c; .

\ \ \ \ ., /

'- ·-~/ tso· \ A

Y•8·2it-4·8 sln 8- ~ ·7cp~ 28. ~~(~~~~====~~~~======~~==~_j

rule for the division of the work would sweep away the last objection to t he design of engines for dyna­mical balance. The primary forces and couples might be balanced, and, as Mr. Schlick had shown the saf!le evenin.g, .t he secondary forces might be approximately ehminated. Professor Lorenz in his paper had shown, in addit ion, that, as good a dia­gram of turning effort could be obtained as hereto­fore.

Professor H ele-Shaw, who followed, said that in Professor Da.lby's paper, read at a former meetina, it was pointed out, in connection with the balanci;g of engmes, that certain quantities must be chosen arbitrari ly, otherwise the problem was indetermi­nate. In t he discussion on that paper the speaker asked what effect t he arrangement of cranks had upon the form of crank-effort diagram with a view to the requirements of balancing. Professor Dalby, in replying to this question at the time, showed by the example of the s.s. Kaiser Wilhelm der Grosse that such an arrangement did not cause a more variable crank-effort diagram t han usual when the cranks were not ball\nced accurately. The speaker did not sup­pose t hat Professor Dalby at that t ime had any idea -as he certainly had not himself-of settling the arbitrary factors of the balancing problem so as to insure the most satisfactory form of crank-effort diagram. Still less was it to be supposed that by such a beautiful application of Fourier's theorem, Professor Lorenz would be able to show that the balance of r eciprocating masses not merely agreed with the best conditions of t urning moment, but was necessary for the most uniform angular velocity of the shaft. The way in which Fourier 's theorem could be applied had just been explained by Professor Dalby by means of some very interesting examples, but he ven­tured to think-and it was the only criticism he had to make- that the concise t hough remarkably clear form in which Professor Lorenz's t heorem and the polygon of tangential forces had been stated, made it desirable that some further examples from well-known engines in practice should be given . If t he author of the paper would contribute, in the form of an appendix, some of his investi­gations founded on engine data which he had de­rived from English and German periodicals, he would confer a benefit upon the I nstit ution for which all the members would be grateful. I t would be desirable that the author should not only give the actual crank-effort diagrams, but also show the way in which, by the application of h is method, the distribut ion might be improved.

Mr. L . Giimbel, of Elbing, had stated in the technical marine journal M nri?te R utLd8chcw, last year the simple relations between the turning

E N G I N E E R I N G. [APRIL 20, I 900.

and contracting the expression (see Fig. 9) F . p . cos [ 1/1 - (a + ~) J - m . w'J. • r cos (a + q>)

. = R cos ( - 'Y (a - «P) ) • we may wr1te

moment and the position of cranks, and, as that was the subject before the meet ing, he hoped what he had to say would be of interest , t hough the explanation he had given was more detailed than that contained in the author's paper. Bupposing the law of steam pressure to be a harmonic law, varying as the cosine of the single angle, he had found the value of the tangential pressure vary-ing as the cosine of the double angle of the crank position. It followed that the fluctuations of t he or tangent ial forces of a multiple engine would be of the most uniform nature if the polygon were closed, the sides of the polygon being proportional to the work done by the cylinder, and directed to tho double angles of the crank. Mr. Gi.im bel had laid down rules which followed for the construction of

T cp = R 1 . cos ( 'Y1 - (a1 + ~)sin (a1 + ~)

+ R2 · cos { 'Y:.!- (a2 + ~)) sin (a2 + q>), &c.

Tcp = ~ . R1 . sin -y1 + ~ · R1sin[2{a1 + «P)- y1]

+ i · R2 .sin 'Y2+~ . R2 . sin [2(a2 + <t>)-y2J.

an engine with three or four cranks, and had proved the usefulness of the method by the agreement of the results with actual practice. Professor Lorenz came to the same conclusion, assuming directly t he law of the double angle for the tangential pressure. But though the author had considered in his paper the steam pressures alone, it was pointed out that the weights could be neglected in the problem in quest ion , but the infl uence of the inertia of the mov ing parts could by no means be omitted, as they contributed largely to t he turning moment. There was, Mr. Gl:imbel continued, also no reason for neglecting them, as t hey could be very eaeily t r eated in the same manner as t he steam pressure, by a vector diagratn. To t he average pressure Tm of the auth or's paper the forces of iner tia did not contribute anyt hing, but they were of the greatest importance, for the expression, varying with the double angle, altered both the vector 's ::,ize and the direction of the same. I t was not possible at t hat time to enter into the details which Mr. Giimbel had previously given, as before men­tioned ; and he would confine himself to repeating shortly the principal points of the investigation .

Fig.7.

H.P.

A.L..

~.8 . • ·--·

-· f)!K,,

Taking indicator diagrams, as in :Fig. 7, and con ­structing the diagram of the actual pressure on the piston -rod, it was possible to replace t he result ing closed curve by an ellip e ; that was to say, the law of the steam pressure could be represented as a harmonic function of the crank angle, as shown in Fig. 8. The following was the formula given :

P (for the angle</>) = F .p. cos (1/1 - ~); if

F = the area of the piston ; p = the maximum pressure on the piston ; tf; = an angle depending on the cut-off of the cylinder,

characterising the origin of the phase. The law of the forces of inertia of the reciprocr.t­

ing parts: P (for the angle 4>) =m. w2 r . cos 4>;

if m = the mass of the reciprocating parts; r = the radius of the crank; w = the angular velocity of crank.

F or a multiple-crank engine, t he cranks, which are moved at a given moment from t he top point to the angles ab a2, a3, &c., the tangential pressure can be expressed, supposing infini te length of the rod, by

T (for the angle ~) = ( F1. p1. cos [tl- (~ + <P)] -?n. w2. r. cos (a1 + <P) ) sin (a1 + ~)

+ ( F ~ . p2 . cos [ ¥'2 - ( a2 + ~)] - m. w~ . r . cos { a2 -t q>)) sin (a 2 + 4>) ;

Pig. 3 . - · ,

\

·"'

• I ' • r·- .. •

f .

\

\ \

•

I f

•

-1- ·-1

I

. ~ .. ·z...

The first part of the expression is, therefore, in­dependent of t he inertia forces :

= ! . R . sin 'Y = ! . F . p . sin 1/1 = T11 •• The second part

! . R . sin [ 2 (a + <P) ·- y J = 8~~ . sin [ 2 (a + «P) - "'J. I t would be easily seen that the size of the

vector !m , as well as the origin of the phase, Sln 'Y

was influenced by the angle Y, or, what was the same thing, it was influenced by the forces of inertia and the cut-off. I t would appear, therefore, firstly, that the great fluctuations in the tangential forces coulrl be balanced, not by the weights of the moving parts, but partly by their inertia, and partly by variation of the cut-off. In the particular case in which the forces of inertia were pro· portional to the work done by the corresponding cylinder, no shifting of one phase relatively to the other occurred in consequence of the inertia forces, and t he forces of inertia could be omitted if only t he angles of the most uniform t~rning l!l~ment were being considered. The relative pos1t10n of the phases of the single cylinder were, further, dependent on the cut-off of the single cylin~er, as the value sin IV had, in the fi rst line, a functwn of the cut-off. With all practical exactness, it would be found that

1 £.l n -4 £

sin 'it = k -7r l - £

where k denoted the ratio of the actual diagram to the ideal one and varied from about 0.8 to 0.9. For enainos 'with normal proportions of slide valves,

0and normal number of revolutions, tl~e

angle 1/1 could be taken as about 60.deg. To obtam the most equal turning moment, It was necessary, as had been shown, that the polygon, the sides of which were proportional to the ~ork done .by the single cylinder, should be closed 1f draw!l WI~h the double anales · and for balancing the engmes 1t was

b ' h f f also necessary t hat the polygon of .t e orc~s o inertia should be closed, if drawn wtth the s1~gle angles. I t was, therefore, by no means, as might be concluded from Professor Lorenz's remarks, an easy task, or still less a natural po~tulate, to f.ulfi l the two conditions at the same t1me i espeCially considering that variat ion of the work do?e byo~~e separate cylinders was practically possible . Y

· M G" b 1 qUite within a. very narrow margm. r. um e .t. aareed with Professor Lorenz that the suppos\~: of the harmonic law of steam pressu:e, pro vi f that the forces due to the reciprocatmg .parts 0 t the engine were not for gotten, ~as .qUite a~x::e enough for practical purposes, cons1dermg th

APRIL 20, I 900. J great saving of time and the clearness of laws could not be attained in any other manner.

In replying to the discussion on his paper, Mr. Lorenz said, in answer to the objections of Mr. Giimbel, that it was stated in the first lines of his paper that the balancing of the inertia forces was desirable. The balance ought to be as perfect as possible ; that is to say, the fluctuations of the first order, as well as those of the second order, must disappear. Mr. Schlick had explained in his paper that, together with the fluctuations of the second order, there would naturally disappear as well the influence on the turning moments, and there­fore the author did not think it necessary to dwell upon this point in his paper. Mr. Glimbel's in­tentions to neutralise the fluctuations of the turn­ing moments resulting from the steam pressure by those of the inertia, would be connected with diffi­culties, as the value of these latter forces did not depend upon the reciprocating and rotating parts only, but also upon the square of the angular velocity. Any variations of the latter-which could not be avoided in practice- would spoil the balance. For these reasons the author again recommended balancing according to the rule given in his paper. But tUJ·ning moments resulting from the steam pressure, as well a.s those produced by the inertia forces independently from each other, would only be possible with an unequal distribution of work over the cylinders.

The meeting then adjourned.

FLUilJ PRESSURE ON PLANE SuRF ACE .

On members assembling on the morning of the last day of the meeting, Friday, April 6, Admiral Sir John Hay, Vice President of the Instit ution, occu­pied the chair in the absence of the President . Two papers were first read and were discussed together, both being of considerable importance and interest. The first was by Professor H. S. Hele- haw, and was entitled '' The Pressure on an Inclined Pla.ne, with pecial Reference to Balance Rudders." The second paper was by Professor G. H. Bryan, and was on " The Action of Bilge !{eels., Both these papers we shall print in full shortly, together with their illustrations. That of Professor Hele-Sha w was a continuation of the brilliant work he has done by means of sending thin films of viscous fluids between glctss plates, in order to illustrate by actual example the action of stream lines. Our readers will remember, in this connection, the paper read by the same author at the spring meeting of the Institution in 1898. The present paper ha.d been written in response to the invitation of the Council, the author stipulating that t he work should be regarded as incomplete. It aimed at the investigation of the relative distribution of the pressure on the rudder, rather than the determina­tion of the whole pressure on the plate; it being concluded that when the distribution was known the naval architect could apply the results at various speeds as required, and obtain a numerical solution for any given conditions so far as to find the centre of pressure and turning moment of the rudder, not less than to consider the effect of any new depar­ture in the design. It was necessary to consider the problem at first in two dimensions only ; that is, to take water flowing in planes parallel to the surface. That would give only approximations to the correct result, but t.he method of thin films had not at present been capable of adaptation to three dimensional problems. The author con­sidered three sections of the subject: (1) The dis­tribution of pressure with stream-li11e flow upon a plane, and specially upon a rudder. (2) The effect of increased velocities in producing discontinuous motion and the pressure w1der such conditions. (3) The theoretical and experimental investigation ?f the problem in three dimensions. The paper w>ts illustrated by experiments, the author showing by means of the lantern the coloured streams of liquid flo~ng between the plates of glass in the manner whtch has already been described in connection with Professor Hele-Shaw's previous work. With­out the aid of these illustrations it would not be possible to make the matter clear, but as the actual effects have been photographed, it has been possible to make illustrations perfectly representing the phenomena. These illustrations we shall reproduce when we publish the paper in full.

Dr: Bryan's paper dealt with a subject of great pract1eal importance, and it is extremely gratifying to find a. distinguished Cambridge mathematician ~pplying his learning to the solution of these prac­tlcal problems of the shipbuilder. In the present

E N G I N E E R I N G.

case the effort has been altogether successful, for the author has been able to account for results in regard to the efficiency of bilge keels, which up to now have puzzled some of our most eminent naval architects. The author's attention was called to the subject by a paper read by Mr. W. J. Luke be~ore th.e Institution of Engineers and Ship­builders 1n Scotland. He was much impressed with the efficacy of biJge keels in extinauishina rolling, as they appeared to furnish a beautifui practical illustration of the properiJies of discon­tinuous motion. At the suggestion of Dr. Elgar, he prepa~ed t~e present paper. There are three ways by wluch bilge keels can destroy the oscillation of a shi.P th~ough the fluid absorp~ion of energy : (1) by viscosity, (2) by the productiOn of discontinuous motion, (3) by the generation of waves. The effects of viscosity manifest themselves more in retarding the motion of the ship than in ex­tinguishing o~cilla.tion ; and . the fact t hat bilge keel~ do not mcrease the reststance of a ship to a considerable extent, shows that their action cannot prin~arily be du.e to .viscosity. A ship which read1ly expends Its osmlJatory energy in forming waves under other conditions, all the more readily absorbs energy from certain types of wa-ves · in other words, a ship which generates t he ~ost waves when it rocks, is most readily set in motion when waves of the proper period strike it. The efficacy of bilge keels in extinguishing rolling motion, in virtue of the discontinuous motions they produce, is materially greater than would be directly inferred from experiments on the coefficient of resistance of a lamina moving in water. In a ship possessing no sharp edges projecting into the water, discontinuous motions cannot exist at the velocities due to moderate rolling ; so the extinc­tion of oscillation in such cases would be due chiefly to wave formation. When a bilge keel is added, discontinuous mot.ion is at once set up ; the fluid motions being divided into two parts by n. surface of discontinuity, thrown off from the sharp edges. It was the purpose of the paper to prove that the ad vantage of the ship with bilge keels, over the same ship without them, can be accounted for by discontinuous motion to a greater extent than would appear at first sight probable. The effects of wave motion were secondary in character, and were left entirely out of account by the author in his calculations. The result pro· duced by pressure variations against the sides of the ship, due to the velocities of the water, was not the least interesting part of Dr. Bryan's in­vestigation ; and a point of considerable import­ance was that which showed how the efficacy of bilge keels depends, not only on the action of the bilge keels themselves, but also on the position in which the keels are fixed, and on the form of the section of the ship .

The discussion on these two papers was opened by :f\1:r. R. E. Froude, who stated, in regard to Professor H ele-Shaw's contribution, that if it had not told him exactly what he wanted to know, he was grateful for the information that it imparted. He thought that there was one poi~t, however, on which the casual reader might be misled, that was the question of the range of speed, and the depar­ture from the type of flow proper to a frictionless fluid towards discontinuous flow as speed increased. Substantially at the lowest speeds of ships and models, the departure from a perfect fluid flow was complete, and there would be no further depar­t ure as speed increased ; he could not, therefore, accept the changes in speed as significant. H e based this remark on model experiments. Pro­fessor Hele-Shaw's experiments were carried out under highly artificial conditions, and between t he two surfaces the viscous resistance in the fluid was practically predominant, and contrelled the action.

Passing on to Dr. Bryan's paper, Mr. Froude de­scribed it as a masterly and valuable contribution to what was known regarding resistances to rolling. The operations, if not new, had not before been put forward in this systematic manner, and the form and position of bilge keels had not been de­termined quantitatively by any previous investi­gator. The paper, t herefore, marked a notable advance. He was pleased to see the effect of the stream-line 1notion was so great. One proposition struck him as new : the author had said that, elitni­nating the effects of viscosity, we are left to deal with discontinuous motion and wave motion. The question as to the relative extent to which the action of bilge keels depended on these two causes

•

might not be devoid of practical interest. It was clear that a ship which readily expends its oscilla­t ory energy in forming waves may, under other conditions, all the more readily absorb energy from certain types of waves ; on the same lines as, in the radiation of beat, good radiators are good absorbers. In other words, a ship which generates the most waves when it rocks is the most easily set in motion when waves of the pro~er period strike it. This proposition of the author s, Mr. Froude said, strikes one as paradoxical; but on consideration he thought it sound, for as stability is given, so is wave­making; that is to say, if the centre of gravity of the cylinder be lowered. The general upshot of the operations here considered did not entirely account for the results of experiment. In saying this, he had in view tha experiments made with the Revenge, and also Sir William White's paper, read before the Institution in 1895. Though the mathematical curves might approximate, they did not actually agree ; so there must be s01nething left. It might be that what Dr. Bryan had said as to the forces of inertia of t he parts of the water set in motion and not brought to rest, would account for this.

Mr. H. H. West thought that the flat ellipse used by Dr. Hele-Shaw, in place of a plane surface, was sufficiently like a rudder on a ship; but there was less flat in the rudder than in his prop01·tions. He expressed sympathy with what Mr. Froude had said, for the experiments dealt only with a re­strained surface of water ; still he thought the method was valuable. The author spoke of the change as gradual ; he would like to know at what point the stream-line motion was destroyed, and what was the critical speed 1 Probably that de­pended on the nature of the fluid. Did the stream lines cease, or were t hey mask ed under conditions of discontinuous flow 1 The proportioning of rudders, as carried out, was entirely empirical, and he was glad to think that Dr. H ele-Shaw's paper would throw light on the subject. There had always been difficulty in estimating the centre of pressure on a rudder, and he had been applied to by makers of steering gear to assist them in t his matter. The speaker also made reference to the dividing lines as shown by coloured bands, and asked how the author had arrived at the position of the dividing band as shown in the diagram; was it a result of actual observation or of plotting 1

The next speaker was Professor Dunkerley, who said t hat he understood objection had been raised to the nearness of the plates in Professor H ele­Shaw's experiments. For his own part he did not wish at present to object to the thinness of the film, but wished to refer to a point which, it appeared to him, was of primary importance, and which, if sus­tained, would probably cause Professor Hele-Shaw to come to the conclusion that before he proceded on the experimental lines sketched in his paper, a preliminary investigation might be neces ary. He would like, therefore, to make quite sure he understood the paper. The author's object ap­peared to be to get the variation of pressure over a submerged body when a fluid flows past it. In the case of a perfect fluid tha.t variation of pressure could be determined from Bernoilli's equation, provided the velocity of gliding over the surface were known. That velocity of gliding could be calculated mathematically in the case of an elliptic cylinder which included, as one extreme case, the flow past a circular cylinder, and in the other extreme case a fiat plate. In such cases the stream lines close in behind the plate. In bodies of more complex fonn t he mathematical di.fficul· ties were too great to be overcome. But if the stream lines of a. perfect fluid were plotted, it would be possible, by increasing the widths at different points of the stream tube immediately adjacent to the solid, to infer the velo?ity at each point, and consequently the pressures In a peJ"feot fluid. It would be possible to plot the stream lines of a perfect fluid experimentally, provided certain experimental conditions wer~ satisfied. Those conditions had been clearly laid down by Stokes in the paper to which reference had been made. This paper, the speaker said, was the basis of the whole matter, and its importance could not be insisted upon too strongly. Briefly, these con­ditions were : (1) The use of thin films; (2) the use of a highly viscous fluid ; and (3) the presence of slow motions, so that the effects of inertia were altogether dominated by those of viscosity. The closer the approximation to these conditions, the more nearly the form of the stream lines of a

t

soB E N G I N E E R 1 N G. [APRIL 20 , I 900.

GENERAL PLAN OF THE PARIS EXHIBITION. (FO't Description, see Page 519.)

MOH TA I

•

F4J.l.

~t~E?~,f~~~~~oF4E~~Ee$r~E~9Eo======1~)~D:=:==:~f~DoM~r~

FIG. 1. GENERAL PLAN.

n

I I I

!o

J)O •

ICO I

----- ...... --- ") - -- - __ ... ... 1~...........: --

,.. .. r-"' ' • • • • • •

' • • ' •

•• ' • • • • • • • • •

' •

' '

- REFERENCE --• I NSTALLATION RAJ LV-'

TRAMWAYS

ELECTRIC POWER CA BLE •

- ·- ·-

-----

FIG. 3. THE TROCA DERO.

perfect fluid was i 111itated ; hut the more they were departed from, the les closoly woulc.l the stream lines of a perfect fluid be imita ted. I t was to be remembered that if these conditions were satisfi ed, the forms of the stream lines of e. perrect fluid were imitated; in all other respects, they were absolutely different from those of a perfect fluid. In Pro­fessor H ele-Shaw's paper of 1898 these conditions were, the sp eaker said, distinctly satisfied, so that

.. any conclu ions based upon the identity in the form of stream lines in the two cases would be correct.

Mr. Froude here asked a question as to the effect of the walls, and Professor Dunkerley pointed out that the problem was s imply the ordinary hydro· mechanical problem, in which there was no slip­ping at the boundary, and in which the velocity was a maximum at the centre. By having an in-

FIG. 2. T HE E sPLANADE oEs 1Nv ALIDES •

definitely thin film it was possible to take, follow· ing tok e ·, the average velocity as determining the stream lines. In the present paper Professor Hele-Shaw had gone a step further. He stated that in an actual fiuid, tho stream lines do not close in behind the phte, but that there was a surface of separation, dividing the moving water from the dead water behind the plate. Lord Rayleigh, by assuming that that surface of separation is a surface of the same pressure as in undisturbed water, was enabled to calculate the velocity of glid· ing at each point , and consequently to obtai~ t~e variat ion of pre . ure in the ea. e of a perfect ~tqUtd. This assumpt ion, the speaker concluded, mtght or might n ot be correct, and if he understood the aut hor correctly, he stated that by the method of thin fi lms he could reproduce what would happen. But, he would ask, how does the author proposo to obtain t his surface of separat ion 1 "By using a less viscous liquid than glycerine.- viz., wat~r- an~ gradually increasing the veloe1ty of the ~hw film. What then did Professor H ele-Shaw thmk he was

' ' h getting 1 I t appeared to Professor Dunkerley, w o spoke, not so much as a critic, but.~ a s~udent of hydro-mechanics who wished his difficulttes to be r emoved that the <luthor would not necessarily be imitat ing the lines of a perfect fluid. In fact, he appeared to be violating t wo of the fundameut~l condit ion laid down by tokes. lie _was d~li· berately decrea ·ing the viscou effect and m~reasmg the inertia effect. In such a case, how did ~r~· fessor Hele-Shaw satisfy him elf that he was 1mt· tating the tream lines of a perfect fluid ? The speaker did not wish to say ~he auth?r was not doina so · he merely asked for mformatwn how the

0 '

E N G I N E E R I N G. =

THE PARIS EXHIBITION. (For Desc1'iption, see Page 519.)

--•

509 ' - author assured himself that he was imitating

the stream lines of a perfect fluid. In his lec­tures at the Royal Naval College, ?e had intro­duced a consideration of these vtscous stream lines, and had proved their identity ":'ith thos~ of a

· perfect fluid in a simple ma.nnor, ~ttho~t usmg ~ stream function. Expressed ver~ br~efly, tf S~okes conditions were realised-that ts, tf the vtscou~ effect is so great that we can neglect in the equa.: tions of motion those terms which involve products of the components of the velocity ~nd their ~if­ferential coefficients- then the equabona of mohon are seen to be

dp d 2 1.£ - = P. -ds fP z

~=0 dn dp =0 d z

•

In these equations, the direction of s is in the direction of the stream line, that of n normal to the stream line, and that of z perpendicular to the parallel plates ; the symbol p denoting pressure, 1b the velocity in the direction of the stream line, and p. the coefficient of viscosity. A very small geo­metrical step, which the speaker stated he would add as a footnote for pli blication in the Transactions, would show that the stream lines as given by these equations were identical in form with those of a per­fect fluid. He would next suppose that a thin film were still used, but that the velocity were increased so that was not so small as to be neglected. In that case, equation (2) would not be true because it would be necessary to consider the pressures necessary to cause centripetal accelerations, neither would the first equation be true because there would be intruded an inertia term. In fact, equa­tion (1) would become of the form

d p = p. d2 1.£ - p u d 1.£ 1

ds d z2 d s

· in which p is the density per unit volume. The point upon which Professor Dunkerley wished to be thoroughly understood was that if eith~r of the terms on the right-hand side of this equation were negligible, compared to the other, there would result the remarkable conclusion that the stream lines would have precisely the same shape in the two cases, although, in other respects, t hey would differ. If neither term were negligible, con1pared to the other, then the forn1 of the stream lines would be held quite different to what they were in the two extreme cases. Even if the experiment were confined to glycerine, so that p. remained the same, it would be noticed that the first term varied as the linear power of the velocity, whilst tho second ter1n varied as the square of the velocity. Thus, at low speeds, the value of p. might be so great that the second term would be negligible compared to the first ; but as the speed increased, the second term increased at a much greater rate than the first, and very soon it became an important factor. In addi­tion to this, Professor Hele-Shaw had decreased p. on account of using a less viscous fluid than glycerine ; and therefore, for a second reason, he made the inertia term of great relative importance. He would again, therefore, ask Professor Hele­Shaw how, in proceeding in the manner suggested, he knew that he was obtaining a copy of the strean1 lines of a perfect liquid. It appeared that Pro­fessor Hele-Shaw was not imitating any special probletn, more particularly that of a perfect fluid; therefore, any quantitative data based upon the method in the paper would be erroneous. ·

These remarks, Professor Dunkerley added, re­ferred to the use of thin films, to which the paper also distinctly referred. If thick films were used, the problem assumed quite a different aspect. But judging from the slide which Professor Hele-Sha'~ had shown that morning, it appeared to the speaker quite impossible to measure the width of the s~re~ms with sufficient accuracy to obtain any quan­tttattve results of real value. The stream lines could only be rendered sufficiently steady by approximating closely to Stokes' conditions ; and when the speed in such cases was sufficiently great ~o cause a plane of separation. behind the plate, 1t appeared that the data der1ved would neither apply to a perfect fluid, nor to flow in open water.

Dr. Bryan followed Professor Dunkerley. He said that the beautiful experiments Professor Hele4 Shaw had exhibited at the meeting must be valued, not merely by the actual results discussed in the paper, but rather by the prospect they held out

•

•

•

•

•

, 5 I 0 - E N' G I N E E R I N G. . [APRIL 20, I goO .. ·~~~~==~~~~===-===~~~~~======~~~~-enabling us to investigarte experimentally di.scon- reference to the stream lines -of the Campa.nia was the ot.her two causes described by Dr. Bryan, both tinuous motions in regions having curved boun- the effect of the aperture at the fe>re side of the of which would operate to resist rotation in the. daries: cases in which Schwarz's method failed. It sternpost upon the flow of water round the rudder same way as bilge keels do in modern steamers was no doubt true, as Professor Dunkerley had and the way it a.ff~cted the steering of the ship. But when considering the case of the middle-lin~ observed, that the stream lines obtained by the use Since the adoption of this aperture by Messrs. keel and the fiat-bottom steamer at the present of liquid films could not be expected to coincide Harland and Wolff in the Teutonic and Majestic, day, it would be found that the movement of with the stream lines of any two dimensional fluid . an arrangement which in their case was neces- water round t he section of the ship set up by motion except in the limiting case considered by sitated by the overlapping of the propellers, rotation was not acting against the middle­~ir George Stokes, when the thickness was very the same device has been adopted in many line keel to increase resistance-as it does in the small, the velocity very small , and the viscocity steamers. In some cases, this had been done in case of the bilge keels-but that it was actina in considerable ; or the opposite case, when t he vis- order that the screws might overlap or be the opposite direction to reduce the resistanc~ to cosity was negligible, the velocity considerable, and brought closer together ; but for other causes it rotation, in ~he same way that normal pressure at the thickness of the sheet of water very great; so appeared not to have been necessary on that the bottom In front of the keel was acting to that the bounding plates did not materially affect account. More than one instance of ships so de- increase rotation instead of resisting it. These the form of the stream lines in the centre of the signed had come before Dr. Elgar's notice, where were a few of the practical points upon which film. The effect of the glass plates was to rapidly the steering had not been as satisfactory as in much light was thrown by the papers just heard, break up discontinuous motion. The fact that in other similar ships not fitted with such an aperture. and the speake~ was sure there are many lessons to the experiments now shown the surfaces of discon- It had been reported that it was more difficult be learned by a careful study of these contributions tinuity kept their form so well, afforded evidence to keep such vessels on a straight course, and in and of all they suggest. Dr. Elgar said that before that Professor Hele-Shaw had actually made an ~urning they could not be so easily steadied upon concluding he would only add that experimen~ such advance in approaching the state of affairs repre- the course required. It appeared to him that this as Dr. Hele-Shaw had shown them were very expen .. sented by the second condition. Dr. Bryan went might be accounted for by the fact that the relief sive to make, and that such investigations as have on to suggest a method whereby the stream lines of pressure against the stern of the ship in front been communicated, which are based largely upon due to discontinuous motion could be determined by of the rudder which t he aperture gave, not only experiments, \nvolve c0nsiderable outlay. One of a combination of the two methods. It was only caused a flow of water, as would be seen by Dr. the chief objects of the Institution is the pro­necessary to obtain the boundary of the region Hele-Shaw's diagrams, to pass through the aper- motion of research, and it seemed to him that the of dead water by the use of the thickest possible ture and behind the rudder, but that the line or time had now come-seeing the large access of film of liquid, of t he least possible viscosity moving plane of demarcation between this deflected current membership received every year and the compara­with the greatest possible velocity. When t he and the current which passes at the front of the tive state of prosperity in which the Institution was form of this surface of separation had been thus de- rudder was not stable. This brou~ht into question now found- for considering seriously whether they termined under the most favourable conditions, the effect of the propellers on the rudder; and should not try to give effect to this important it was only necessary to cut out a thin sheet of here, Dr. EJgar remarked, Professor Hele-Shaw's object. This was not a question, at any rate at the metal of the same form, and by then experiment- stream lines were only such as would be formed stage, for a general meeting ; but he hoped the ing with the thinnest possible film of glycerine, he by a sailing ship, and to a great degree by a Council would soon see their way to take the matter would obtain coloured bands exactly reproducing the paddle steamer, or by other vessels whose pro- up, and to try to make some arrangements by which stream lines of the discontinuous motion of a per- pellers were not in the stern. In the case of screw work of this kind-by which the members of the feet liquid. Referring to the actual problem of t he propulsion all stream-line action must be absolutely Institution benefit so largely-could be promoted rudder, Dr. Bryan pointed out that discontinuous dominated by the movement aft of the large masses and extended. motion was an important factor in steering. I t was of water that are thrust astern by the propellers. Mr. 1\facfarlane Gray said he observed that Dr. true that such motion entailed a certain loss of It was possible that in the case of a twin-screw Hele-Shaw in his remarks, and also in his paper, energy, which must be supplied by the engines. But steamer with an aperture in front of the rudder, used the expression "turning moment of the in an ideal perfect fluid, a ship with a rudder which the line of deviation between these two streams rudder, " in a sense which must be misunderstood by produced no discontinuous motions might be not might not be stable. It might oscillate backwards the members of the Institution. According to the inappropriately termed a "perfect tub," which and forwards to some extent in t he aperture on language of naval architecture, the "turning mo­would go on for ever drifting along in the same each side of the rudder post. An important point ment of the rudder " was quite different from that straight line; and the only effect of the action in connection with the action of t.he rudder, which is meant in the present paper. Supposing, of the rudder would be to cause the ship to illustrated by Dr. Hele-Shaw's stream lines, was he said, there were standing upon the table a turn round more or less broadside to the course as to the effect of viscosity in modifying t he steamship model, say 4 ft. or 5 ft. in length, with in which she was drifting. To change the course pressures upon the back and front of the rudder. a balanced rudder. If one were to hold the two of a ship, discont inuous motions must be set up. The importance of this would be seen by referring edges of the rudder with two hands, pulling one and Dr. Bryan had from the very outset urged Professor to the Tables of pressures upon the rudder given, pulling the other if the strength applied were suffi­Hele-Shaw to take up the subject of discont inuous for these showed how high a figure might be reached cient, and the rudder in the model strong enoug~, motions ; and the fact that such motions had now at high speeds. Coming to Dr. Bryan's paper, it would be possible to t urn the model round hon­been seen thrown on the screen was a matter for Dr. Elgar remarked that were many points in zontally and the power would be applied by the tur~­congr~tulation. it of very great practical interest. It was not ing moment impressed upon the rudde~. It was this

Dr. Elgar said he knew that both Dr. Hele-Shaw long ago t hat the battleships of the Revenge and turning moment that was referred to m Dr. llele­and Dr. Bryan had doubted whether these papers Resolution clp.ss were not fitted with bilge Shaw's paper. The speaker wished to point out, would have practical value or practical interest for keels, because the calculations made at the however, the <lifference between what he had d.e· the Institution. He was sure he was expressing time, with the best knowledge then available, scribed and the turning moment of t_he rudder 1~1 the opinion of all present when he said that they appeared to show that the extinctive effect of the steering of a ship. In the ima~ary e~pen­regarded investigations of that kind as possessing bilge keels would not be great in ships of such menton the model which he had considered, if the both these qualities. The sketches of rudders large size and inertia. This was afterwards found strength applied were sufficient, the hull would be and sterns of the four ships shown by Dr. not to be the case, and bilge keels were added S\\'ung about the rudder post, which would b~ a H ele-Shaw, from which stream lines had been with very great advantage. But Dr. Bryan had stationary centre. There was always such a turnmg obtained, were for two cruisers of the Admiralty helped very considerably to show why the extinc- moment on a rudder in action, but this .was not t~e type, a 30-knot torpedo-boat destroyer, and the tive effect of bilge keels was greater than had been turning moment that steered the ~b1p, a~d 1~s Atlantic liner Campania. It was true, as had been supposed. Dr. Elgar agreed t hat Dr. Bryan had magnitude was so insignificant that It was. mvat· pointed out, that t he stream lines, as given by Dr. not yet discovered all the causes of that difference; ably, and properly, disregarde?. The steermg 0 a Hele-Shaw, were only for two dimensions, and but he had certainly pointed out very clearly two ship was analogous to the steermg of a wheelJ:>arrow, were for water lines that are parallel to the surface of what, he should think, were principal causes. the rudder corresponding to the man holdmg the of the water, thus leaving out of account any ver- These were, first, the increase of resistance due to shafts of the barrow. To steer the man had to put tical motion. He did not think that, in the case of reverse currents which act upon the bilge keels; side pressure on the shafts, himself walking sideways the first three types of ships mentioned, this was and, second, the increase of normal pressure upon to the extent of the arc described about the tread .of material importance, as it would be seen from the bottom of the ship, immediately in front of of the wheel. The side pressure applied by the the form of the sterns that there would be li ttle the biJge keels. These two causes of increase of man, multiplied by the horizontal length from ~he vertical motion of the stream lines, and that the resistance had been shown by Dr. Bryan to produce tread of the wheel to the man, was .th~ turnrng real stream lines would not differ much in degree, results which were surprisingly important. It was moment steering the barrow ; and similarly the and certainly not to any important extent, from fortunate that t he position for bilge keels adopted effective side force on the rudder, transverse to the those shown by Dr. Hele-Shaw. The same remarks upon the bottoms of ships, for purposes of practical line of keel multiplied by the distance from rudder would not., however, apply to the stream lines convenience, happened to coincide with the posi- to forefoot was the "turning moment of the shown for the Campania. In her case, the third or tion in which both of these cases of increased rudder " k.n'own to naval architects. In the case of vertical dimension was of impm·tance, as there efficiency were at about a maximum. There were the rudder this side force was the component would be very little, in the actual ship, of the many persons who yet believed that a middle.line transverse to the ship, o~ the differen?e betw~~ effect-shown in Professor H ele-Shaw's diagram- keel was more effective than bilge keels. Dr. t he pressures on the two s1des. The diagra~ of the propeller boss upon the motion of the Bryan's explanations show why t he middle-line hibited and Dr. Hele·Shaw's experiments t re~ water. It must be remembered that the water keel is not so effective in modern ships as it was additional light on this action. They s~o~e d line shown through the boss represented t he formerly. In the old days of sailing ships there that the divergence produced by a de ec e fluid motion and disturbance that would occur was very great rise of floor, and the form of the common rudder notably increased the p;es­if the sternpost were of the full width of the boss bottom was so different from t he present, t hat the sure upon the deadwood of the ship, be ore from water line to keel. In this case it would be keel was attached to what was then t he most pro- the rudder on the side to which the rudder was

· · · h f h · d h m· cli'ned. 'WI'th this increase of pressure th.ere was apparent that the third dimension was all im- jectmg p01nt In t e contour o t . e sectwn ; an t e sur portant, especially as the bossing out of the plat- same remark applied to an even greater extent to virtually an enormous increase of the steer1gth -ing was so formed as to cause the water to pass the yachts of the present day. In both these cases face acting to swing.the ship. The study ~or :~: this proJ' ection by motion in or near a vertical the middle-line keel was effective, not only on diagrams should Increase our esteem lines

· f · · t b t 1 b f common rud~l~>r and the more the stream plane. Another point of practical importance m account o Its own res1s ance, u ~ so eca.use o ,. y

I

•

APRIL 20, I 900·] E N G I N E E R I N G.

about the balanced, or the pa~:tially balanced, line widened out just at the point of maximum rudder were looked into, the n1ore unsatisfactory did pressure, · but here the meeting had had an oppor­they appear to be. In several of the diagrams for tunity of seeing from the actual experiment how balanced rudders, t·he pressures on the two sides are easy it was by reducing the flow to .make this the same, ~here is then no ~iffe1;ence ~f pressures central line as fine as might be required, and in for producmg the naval architects turnmg Jl10ment one of the figures, which was a reproduction of of rudder. the actual p hotograph, there was shown at the back

Dr. Bryan here remarked t hat the pressures re- of the plate the point in question in a most un­ferred to by Mr. Macfarlane Gray would tend to mistakeable manner, that being the point at which turn the ship the opposite way to that due to the the two streams re-united. inolination of the rudder. Professor Dunkerl~y had raised what might be

Mr. Macfarlane Gray, in reply to this remark, considered the most .impor tant question that had eaid he was assuming that the two sides were the been asked, viz., whether the author was sure that same as they appeared to be nearly, but Dr. Bryan when discontinuous flow was obtained at the back 9f mea;t that the action of the equal pressures in Dr. the plate, he had perfect stream-line motion in front, Hele-Shaw's "turning moment of .. rudder, " and his and he also generally raised the question as to the remark was, therefore, quite correct ; it would accuracy of the method when cer tain limits of thick­swing the ship to port instead of to starboard. ness in t he film were exceeded, or , what was practi­A.ccording to the diagrams, there could be no worse cally the ~a me thing, when the fluid used was below design for steering a ship than a balanced rudder. a cer tain viscosity. This mat ter was 0f vital impor­The effective side pressure- being the difference tance, and it was for t his reason that the speaker between the total pressures on each of the two had treated the t wo questions of true strean1-line sides- was enormously diminished, and in the case motion and of increased velocit ies producing dis­c£ a rudder close to the s.tern the excess side pres- continuous motion in two different sections. Con­sure on the deadwood was entirely lost. But this cerning the former, upon which all his calculat ions would apply only to sailing ships, and the speaker were based, there had been no question raised bad not heard that balanced rudders had bet3n while in the latter, in answer to Professor Dunker~ employed in them. In conclusion, Mr. Gray bore ley's inquiry, he most emphatically expressed his test.imony to the value of both Dr. Hele-Shaw's and belief t hat true stream-line motion no longer existed, Dr. Bryan's papers, though he had not taken in all either under experimental conditions which he had the mathematics contained in them. dealt with, or in the actual flow around a rudder.

Professor Hele-Shaw, in reply to the discussion, rMat hematics had indeed been applied by others stated that Mr. Froude had spoken upon the ques- under these conditions, and the results would no tion of a growing departure from one type of flow doubt, approximate t o the truth even when w~ter to another as the speed increased, and had given it is considered to act as a perfe~t fluid · but he­as his ~pinio~ that there was pract ically one type Lhe spea~er-thought that the real result could only of flow m .which t~e speed vaned as the square of be ?bta1ned mathematically by treating the fluid the velocity, wh10h occurred even at very low as VIscous. The mathematics of a viscous fluid were sp?ed~, and that until ~ctu.al cavitation occurred ho.w.ever, so admittedly difficult that it was very sur~ thlS kind of flow was maintained. Mr. Froude had pr1smg that such cases as the one under discussion admitted, however, that in the experiments which had not even been attempted, or if they had been bad been shown,, there ~as~ gra~ual chan~e from attempted, there was, as far as the speaker knew, perfect stream-hoe motwn 1? which the flutd pres- no published record of such an attempt. The re­sure was th.e sa~e on ~oth sides of the plate, to a marks of Dr. Bryan, who was very justly regarded state of thmgs In which turbulent flow occurred as one of the highest mathematical authorities were behind the plate. ~· Froude, the speaker said, ·very gratifying, and he-the speaker - could not no doubt based hts rem~rks largely upon the help expressing the satisfaction he felt that his own actu~l meas.urement of resiStance on plates, con- experiments on discontinuous flow had been thought cermng which he was probably better able t o to opportunely illustrate several points in Dr. speak than anyone else; but what had real~y B.ryan'~ own paper. He had not taken part in the been meant by the gradual change referred to m dlScussion on Dr. Bryan's contribution, and he the paper was not so mu~h a gradual change in the would, therefore, like to say then how clearly the c.haracter of the flo.w as m the form of the stream remarkable action of bilge keels had been made by lines th.emselves In front of the plate. These what they had then heard. He felt sure those in­~tr~m lmes. were .shown to change their position terested in the mathematics of the subject would 1~ t~e expenment m front of the pla~e as t he velo- value the promised statement by Dr. Bryan of the otty mcreased, as he ~eant to sho~ 1n the paper, processes by which he had arrived at his results. ~hen he state~ that a ~ery considerable change Dr. Bryan thanked the meeting, and more espe­m th~ stre~m lme occ~rs 1n !ront of the. plate a~ ciallr Mr. Froude an~ Dr. Elgar, for the kind re­the dtscon~muous portwn behind chan~es In form. ceptwn accorded to his paper. In the discussions It wa~ qUite true,.~ Mr. Fro~de sa1d, ~hat the that afternoon, so much had been said about "per­ex~er~mental conditions were m a certain sense feet fluids ," that he feared some confusion had art1ficta~ ; but there had ~een hit~erto very little arisen in the minds of those pre~ent as to which connectiOn between experi~ents hke those of Mr. properties referred to perfect fluids and which not. Fro~de and. the mathemat10a1 treatment of the Stream-line motions without discontinuities existed subJect, wh10h was even more artificial. T~e iJ?- perfect fluids flowing past rigid boundaries, pro­speaker had, .therefore, purposely commenced h1s vide~ th.at no sharp angles or edges projected into paper by statmg tha.t the attempt brou~ht forward the hquid, and that the velocity round the rounded connected. ~he t wo methods by expenments that corners was not so great as to give negative pres­~ould be VISible, but must be regarded as at present sures. When these conditions were violated dis­mcomplete,. though he hoped they would lead to continuous motions were set up, but these 'were bmch more Important results .on what was admitted none the less Jnotions peculiar to a perfect liquid. Y ev~ry one to be su~h a difficult problem. The In his paper he had pointed out that the effect of

quest~on had been raiSed at what velocity the viscosity was actually to gradually break up the ~xpe~m~nts had been made, and here, again, it surfaces of discontinuity. He further pointed out st:!a 0 . e und~rstood that. as .long as perfect that Lord Rayleigh had shown that a balanced

1 ~·l~e mot1?n was ma1ntained, the actual rudder sets itself across the stream when the

ve ?Cl Y ad nothmg ~hatever to do with the ex- motion is discon tinuous no less than when it is con­~~~Iments . . He ~ad ~ned to show ~hat by .working tinuous .. Mr. Froude had pointed out th9.t experi-

resul~, m which, If the stream-lme motwn were ments with the Reveno-e did not seem to fit in :~~tdbedfto h~ld, the actual pr.essure on a~y body altogether with the hypothesis that the gradient m· ht be ou~ on any assumptwn of velo01ty that of the extinction curve consisted of two terms fo~g

1 kn~~n~Oeb~d he had calculated the pr~ssures proportional ~o the first and second powers

to th b 'k· ts, and 30 knots. When It came of the amplitude. Dr. Bryan's paper being the s:co~e; ~~t up of. the flow, he had explained in ~ritten in very limited time, he had not yet con­he had trieJ to ~ his pape~ that the. only ~esults sidered the mathematical meaning of these two character of the ~h~= were. In connectwn With t~e terms: But there was one point on which further this part f th geh whlCh would occur, and In expernnents would be of great value. Supposing give an ° nu~pape~ e had made no attempt to a ship displaced first thl'ough an &ngle of 5 deg., asked h~w it we~c~h results .. Mr. West had and then t~rough an angle of 10 d eg., and started central position f ttt h~ arrived at t~e exact f~om. rest m each case, was the gradient of the ex­to find the stre 0

1. le co ?ured ~ands In order tinctwn curve the same at starting in the first case

had been obta' an~ mea .with wh10h the results as in the second case, when the amplitude had enough exce?t i~~ · Tlushof course was easy fallen to 5 deg.1 It was important t hat this point

e 9ase w ere the centJ·al etream should be tested, as it wopld afford an in9..icat ion

of how far bilge-keel resistance was affected by motions aet up in the wo.ter in previous oscillations .. In conclusion, Dr. Bryan thanked the- Institution of Naval Architects for receiving his paper, and expressed his gratification that mathematician~ were enabled to bring their work before a •body o~ practical men, in bhe hope of effecting a closer union between theory and experiment. t

'

DEPTH OF WATER ON R ESI STANCE OF SIDPB. . A paper by Major Giuseppe Rota, of the Royal

Italian Navy, on ''The Influence of the Depth of W ~ter on t he Resistance o.f Ships," wa~ next read. Thts paper we print in full on page 528 of the present issue, and we shall therefore proceed at once to deal with the discussion, in which Mr', Froude was the first speaker. In regard to the torpedo-boat referred to, he said that the hump in the curve coincides with the conjunction of the wave rates ; that is to say, the length of wave cor­r esponding to t he boat and that due to the speed. Under such eircumstances, the shoaling of the water would naturally lower the hump. I t was here a repetition of the old experiment of Scott Russell's, of the fly boat towed at great speed in a canal. The solitary wave was unable to keep pace with the boat, and so no wave-making resistance was set up. In the experimen ts under consideration, on t he same principle, as the water shoaled there was an approach ~o that criti~al poin~, resistance greatly increasing m t he meantime, until t he point was reached when the wave vanished and the resistance fell off pro­port~onately. The results of the paper were ex­ceedingly valuable. For a long time they had in­tended to make experiments of a similar nature at Haslar, but had been too busy. Such experiments, more~ver, were very costly, and they were therefore more Indebted to the author for making them public.

Mr. A. Denny said that at Dumbarton they had made experiments to t est the effect of shallow draught on resistance. They had put a false' bottom in the tank, and had towed models. The object had been to firtd out what speed could be guaranteed for shallow rivers. The results, how­ever, obtai~ed were so various that they came to the concluswn they could get no definite data: sometimes the paddle-wheel would be over the hollow of the wave, whilst with the screw propeller there might be no water at the stern at all. In fact, they had sometimes pushed all the water out of the tank.

Mr. C. Humphry Wingfield observed that as no reference was made to Captain R asmussen's work i~ this matter, the author had probably overlooked h1s remarkable paper of last year, and the earlier one on the same subject published by Captain Ras­mussen in vol. lviii.. of EN~INEERING, page 337. These papers dealt with full-s1zed vessels, on which numerous experiments had been made under very favourable conditions and with great care; and he fe~t that, however . admirable these experiments wtth small models might be, they had not quite the same weight as those with the act ual vessels. In a letter to Mr. Wingfield, Captain Rasmussen had mentioned that some time was always required for the wave system to accommodate itself to the depth of water; and he would, therefore, be glad if the author would state for how long a distance the bottom of the tank was raised. Another point mentioned by Captail\ Rasmussen was t he necessity for an absolutely rigid bottom in order to obtain trustwor thy results; or at all events one of sufficient stiffness to prevent its following any ten ­dency to adapt itself to this under -water wave form. He presumed this had not been overlooked. Some fi gures showing the influence of depth of water on th~ ~peed of .Bri~ish warships had been given by Sir ~1lham White In a ~aper on " Recent Experience With_ SOf!le of He! MaJesty's Ships, " read before the ~nstitutwn, Aprll 7, 1892. Mr. Wingfield thought It Yery probable that the author was correct in ~ttributing to change of t rin1 a large part of the Influence of this bottom. As an instance he might mention the Boadicea, a launch built by Messrs. John I. Thornycroft and Co. It would be found recorded on page 494, vol. lxiv., ENGI­NEER~G, that she was perceptibly faster with only a few Inches of water under her than when in some­what deeper water.

This brought the morning sitting to a close.

(To be continued.)

BRAZILIAN TELEGRAPHY.-The submarine cable be· tween Para a~d Pernambuco is about to be doublt d tu tPeet the requtrements of a growing busines~

•

•

'

• •

•

•

•

•

•

•

•

•

E N G I N E E R I N G. [ APRIL 20, 1900 . •

ENGINES OF THE CHILI AN CORVETTE " GENERAL BAQUEDANO."

•

..

CONSTRUCTED BY :ME,'. R, . H AWTHORN, LE, LIE, AND CO., LiftHTED, NEWCASTLE-ON-TYNE.

( fl'm- Description, see Pagt 525. )

•

\ .

•

•

' •

•

T HE l NSTIT UTl ON OF MRCRANJOAL ENGINE~RS GRA· DUATES' M EETING. -The seventh :meeting of the Graduates' Association was held at the Insti tution of Mechanica.l Engineers, Storey's Gate, W estminster, ab 7.30 p.m., on Monday evemn2', April 9, Sir William Arrol, member of council, M.P., LL.D., in the chair. Reports of the vi~:~its to the Tower Bridge and the Tower Station of the Central London E lectric Railway, Shep­herd's B ush, were read by the honorary ~ecretary~ and di.Eicussed by the graduates. Mr. H . M. R ootna.m, graduate, in opening the d iscussion on the Tower B ridge visit, ga.ve a ve~y ioter~ting descript~on of th~ pum~ing station, hydra.ultc machmery, controlhng gear m cabms, and many other i n~resting details in conl?ection with the working of t he basoul~, &c. The ch~1rman called attention to the construct iOn of the cba.ms, hall-and­socket bearings on the ~p of each column for a.d_j us~ment of the weights, controllmg gear for rockers, lubn~atton of all joints whilst un~er 30 tt!ns pr~ssur~. and othermterest­ing details. An mterestmg dtscuss1on. followed. Mr. J . Schontbeil, graduatP, opened tbe d1scusston on t~e visit to the Tower Stat.ion of the Central London E lectnc R ailway, S hepherd's B ush, by givi_ng a v_ery interesting description of the compoun~ Alhs . engmes and a.lter­nating dynamos. The meetmg, wh1ch was the last of this ~ession terminated after hearty votes of thanks had !>Pen pro~ed, seconded, and ~a.r~ed , both to M r . . Edgar W ortbington, secretary, for his. ki~dness and asststan?8 in starting tbe Graduates' AssoCiat iOn, and to Mr. Martm G . Duncan, honorary secretary of the Graduates' Asso­ciation, for his very able management as regards papers, visits, &c.

•

l!'IC. 1.

El&· !J..

-•

I

•

•

APRIL 20 , I 900. J E N G I N £ E R. I N G.

•

•

•

'

OF THE C R\TETTE " GE ERAL BAQ E DANO." CON TRUCTED BY ~lE.' ' H, '. IL\ \\'THORN, LE 'LIE, A D CO. , LI ~llTED, r E\YCA. "l'LE-ON T\" ~K

( For Description, see Page 525.)

• •

•

•

•

I

•

•

FIO . 2 • •

------

./JSJO

-

•

'

• •

\ \

•

• •

•

•

•

•

-

•

•

•

•

•

,

•

' '

•

• •

•

•

•

I

•

'

t

•

l

- ----

NOTES FROM THE NORTH. GLAsGow, Wednesday.

Glasg011J Pig-Iron Ma~rket.-A fair amount of business was done in the local pig-iron market last Wednesday, and realisations in Scotch iron knocked 6~d. per ton off the price. Cleveland, on the other hand, rose 3d. per ton, and hematite iron fell !d. per ton. The sales in the forenoon amounted to 20,000 tons, and in the afternoon to about 15,000 tons. Prices at the close were 3~d. per ton better for Scotch iron. The settlement prices were as follow : Scotch iron, 77s. 6d. per ton ; Cleveland 78s. 7! d.; Cumberland and MiddlesbTongh hematite iron, respectively, 86s. 9d. and 87s. per ton. On Thursday forenoon the market opened somewhat ex­citedly. Scotch warrants star ted at 77s. 6d. per ton cash and suddenly dropped to 76~. 6d., and, after some fluctuations, left off at 76s. 7;d. per ton buyer~, being a decline of 10d. per ton. Cleveland declined 1!d. per ton, and Cumberland hematite iron fell to 86s. 5d. per ton buyers. The turnover would be about 15,000 tons. The market went strong in the afternoon, when about 10,000 tons were dealt in at appreciable ad­vances. Scotch closed 6d. per ton up on the day at 76s. 11~. per ton cash buyers. The settlement prices were on Thursday afternoon 77s., 78~. 7!d., 86:i. 9d., and 87s. per ton. Friday and Monday were holidays, and when the market was resumed on Tuesday forenoon the tone was easier, though reports as to trade were re­garded as good. Scotch iron fell 4~d. per ton, and Cleve­land and hematite iron fell 3d. each. In the a fternoon the market was flab on some realising, and the want of fresh buying, a dull tone prevailing on account of the Easter holidays in E ngland. Scotch closed 10d. per ton down on the day, Cleveland 6d., and hema.tite iron 1s . per ton. The sales for the day amounted to 25,000 tons, and the settlement prices were : 763. 1! d., 78s. 1!d., 85s. 9d., and 8'i's. per ton. The market was very excited this forenoon on the reported sharp break in the price of iron and steel in America.. Some of the cables seem to show that the break is not wholly legitimate. However, 35,000 tons were sold this forenoon, and as a. result of the pressure Scotch iron fell 1s. ~. per ton. About 15, 000 tons changed hands, and Scotch iron fell other 2d. per ton. The settlement prices were : 743. 9d.1 77s. 7!d., 84s. 9d., and 97s. The follow­ing are the shtp_!Dents of pig iron from Scotch ports last week : To the U nited Sta.test 415 tons ; to Canada, 162 tons; to South America, 182 tons; to India., 217 tons; to Australia, 285 tons; to Italy, 1180 tons: to Germany, 1385 tons ; to Holland, 1395 tons ; to China. and Japan, 105 t ons; smaller quantities to other countries, and 4450 tons coastwise. The total for the week was 10,148 tontt, against 3537 tons in the corresponding week of last year. The following are the quotations for No. 1 makers' iron: Clyde, 893. 6d. per t-on; Calder and Gartsherrie, 903. ; Summerlee, 92d. 6d. ; Coltness, 93s. 6d.-the foregoing all shipped at Glasgow; Glengarnock (shipped ab Ardros­san), 88s. ; Shotts (shipped at Leith), 92s. 6d. ; Carron (shipped at Grangemouth), 9ls. per ton. The records of the past week have again touched levels that have not been reached since 1874. Speculation has been active, but it received rather a severe check on Tuesday by the receipt of somewhat unfavourable news from America. Fresh buying either from home or Continental consumers is at almost> a complete standst ill, but the weight of old orders keeps the market cheerful. Makers' prices have not responded to the recent advance in war­rants. There are still 84 furnaces in blast, as compared with 82 a year ago. The stock of pig iron in Messrs. Connal and Co. 's warrant stores stood at 165,898 tons yesterday afternoon against 171,395 tons yesterday week, thus ~bowing a reduction for the week amounting to 6497 tons.

Coltncs3 Iron Company: A cquisition of Milnett iln Spain. -Dnring the pa..~t half-year the Coltness Iron Company, L imited, have acqnired an interest in two extensive iron ore p_roP.erties in Spain. These are (1) the Alquife Mines and Railway Com~any, Limited, registered with a capital of 450,000l., of wh1ch two-thirds (300,000l.) are guaranteed by the Coltness Company, and the balance by a well­known firm of Cumberland ironmasters. The mines are situated in the Province of Granada, about 62 miles from the port of Almeira, and the present output of ore is about 2000 per week, but with additional railway plant, arrange­ments for which are in progress, this output will be trebled. The securing of these mines-which have been purchased outright, thus getting rid of future royalty charges­greatly improves the position of the company by a.ssurin~ for many years a. plentiful supply of pure rich ore at a. low cost. (2) The Ba.cares Iron Ore Mine3, situated in the province of Almeria., and in the neighbourhood of the Alquife Iron Ore Mines. These mines are held by the BacareCJ ~lines, Limited, one-fifth of whose capital­namely, 25,000l. -has been subscribed by the Coltness Company, the other shares being taken by other English and ticottish ironmasters. The mines are held on lease. The ore is of high-class quality, and will form a. valuable a.ddition to the Coltness mineral supplies. The autho­rised capital of the Coltness Iron Company is 1,000,000t., and the issued capital 700,000l.

Blast-Fwrnacernen's Wages and Conciliation B oard.­A conference was held in Glasgow la.st Friday between Scotch iron masters and repreaentati ves of the blast­furnacemen to consider the demand of the la.tLer for an advance of 10 per cent. in wages. The proceedings . w~re conducted in private. After a somewhat lengthy s1ttmg it was intimated that both parties had agreed to the formation of a. Conciliation Board, and rules governing the same were settled. The masters further intimated that they were prepared to agree to a minimum wage. After a long conference, the men agreed to accept the employers' offer of 5 per cent., beginning May 1.

E N G I N .£ E RI N C. Glasgow Copper M arket.-Copper changed hands yester.

day week to the extent of 25 tons at 79l. for April 30. On the following day things were quite nominal. Y esterda.y the metal w~ not dealt in, and in the afternoon the quo­tations were 78l. 10s. per ton ca.sh buyers, and 77l. 7s. 6d. three months. The set tlement price of copper this after­noon was 78l. 17s. 6d. per ton, but no business was done.

Pri1tce's Dock Railwcty, Greenock.-The contract for the construction of the Prince's Railway, Greenock, has been placed with Messrs. Robert M'Alpine and Son, G lasgow. The railway runs from Ibrox Station, near Glasgow, to the docks, and is to be constructed by the three leading railway companies.

New Swing B ridge at Lei th H arbour .-The new swing bridge across the harbour of Leith, which connects the theroughfares of Bernard-street and Commercial-street, was lately swung successfully and the barriers cleared away preparatory to the openmg of the bridse for public traftic. The bridge weighs 340 tons, and lS swung by hydraulic rams, one for opening and one for closing the bridge. It travels on rollers on a. rail laid on the ~asonry, and piling erected at the Berna.rd-atreet side. The total cost of the structure is about 8000l.

I mportwnt Extension to J ohnston Gas Works.-The CC'Ir­pora.tion gas manager at J ohnston, Mr. Deans, has sub­mitted a. statement to the Police Commissioners pointing out the imperative necessity of important additions being made to the ga.s works involving, at least , an expendi­ture of 15, OOOl.

Locornot i11e Con~racts .-Messrs. Sharp, Stewart, and Co., of the Atlas Locomotive Works, Glasgow, have recently contracted with the Midland Railway Company to build 20 express engines for them. They are to have four wheels coupled, 7ft. in diameter, with a. four-wheeled bogie in front, and a six-wheeled tender. The Atlas Company had already secured orders for other 18 engines divided between the Dutch Rhenish Railway, Brazil, and New Zealand.

Order for Two Paddle Steamers.-Messrs. Ritchie, Graham, and Milne, Whiteinch, have been commissioned to build two paddle steamers intended for servjce in India.. They will be 250 ft. long, 45 ft. wide, and 11 ft. in deJ.>th, and they will be fit ted with turntables and rails 1n order to enable them to carry trains over the Hooghly.

NOTES FROM SOUTH YORKSHIRE. SHEFFIELD, Wednesday.

Engilneers visit Sheffield.-Two important bodies of en­gineers visited Sheffield lnst week. The Master Cutler, .Mr. R. A. Hadfield, had as hi.a guests a. party of some 30 South African mining engineers, who, owing to the war, are temporarily out of employment. They were shown over the Newhall·street Works, and also Mr. Had­field's premises at Tinsley. The students of the Glasgow U niversity Engineering Society spenb three days in the city visiting various works, where facilities were given for inspecting the light and heavy trades of the city.

Widening of the Midlatnd .Railway.-The extensive scheme in connection with the widening of the Midland Railway between ShiplP.y and Apperley Bridge is fast approaching completion. The new tunnel will, it is ex· pected, be finished in about t hree months' time. Whereas the old tunnel was constructed of stone, the new one is built entirely of bricks, and is barrel-shaped. It will be about three-quarterd of a mile in length, and will be used for passenger traffic exclusively. The widening of the line on the Shipley side of Apperley Bridge Station, although an extensive undertakmg, is progressing satis­factorily. The Apperley Bridge Station will be removed some 300 yards down the line in the direction of Leeds.

H ull Electric Tra;mways.-In connection with the Holderness-ro~d section of the Hull electric tramway system, considerable difficulties were met with ab a. point where the North Bridge crosses the R iver Hull. Here the engineers had to devise means of maintaining the current of electricity while the bridge was open for the passa~e of shipC\, and also of automatically connecting and dtSconnecting the wires. These difficulties, however, have been overcome. The cables which feed the Holder­ness-roa.d have been carried under the bed of the river, and the automatic switching of the overhead wires has also been successfully achieved. The section was in­spected and sanctioned by Lieub.-Colonel Yorke last week.

Steel and Iron Trades.-In the heavy branches of trade the Easter holidays were shortened as much aa possible. Some of the large works only closed on M onday, but it was W ednesda.y morning before others resumed operati0ns. In every department there is plenty of work on hand, and for railway and othet· material contracts continue to be placed. The chief difficulty with many firms is to obtain adequate supplie'3 of raw stuff. M akers of machinf\ tools are well booked, and there is a sustained demand for vices, anvils, sledge ha.mmena, and similar requisites. The rolling mills are well employed, A-nd on account of the increased cost of workmg, the proprietors have further shortened their discounts by 5 per cent. A con­siderable weight of steel is being dealt with by the tilts and forges.

South Yorkshire Coal Trade.-The past week has been one in which little work has been done, the Easter holi­days having been somewhat extended. Some few of the pits opened yesterday, hub it is not expected there will be any general resumption before Thursday. There has been no notable change in prioes this month. Manu-

[APRIL 20, 1 9oo. facturers ha.ve to pa.y as much as ever for their supplies. but sm_a.ll ~nsumers are treated a little better. A slight reductiOn m the rates for house qualities is expected next month.

NOTES FROM CLEVELAND AND THE NORTHERN COUNTIES.

MlDDLESB~OUGH, W, ednesday. The. Olevelafn:d I_ron Trade.-Ow10g to hohda.y making

t~a.de l~formation JS very scarce, and the fixing of quota­tiOns 18 no easy matter. After having been closed for five days the Royal Exchange here wa.s ra­opened to-day, .hub very few people attended, and next to no buamess was transacted. Sellers would not quote below 78s: fo.r prompt f.o.b. delivery of No. 3 g. m. b. Cleveland p1g tron. Some sales were recorded ab that price, which may be regarded as the general market quotation. We did not hear of any sales of the lower q ua.lities. N omina.Jly, Foundry 4 was 76s. to 7Gs. 6d. and gr~y forge 75s. to 75s. 6d. Middlesbrough warrants 'were qUiet at 77s. 7~d. ca-sh buyers. East coast hematite pig was very stron~ at ~7s. 6d. for ~rly delivery of Nos. 1, 2, and 3, and little non was avatlable for sale. Spanish ore was steady. ~u~io wa.s pat at 2la. ex-ship Tees, but some firms were mclmed to hold out for a rather higher figure.

M arvufactured Iron CliT1.d Steel.-Very little new can be r eported of the finished iron and steel industries. Most of the works have been closed for the holiday~, and this is likely to give customers more ground for complaint of inadequate deliveries. Quotations all round are the sa.me as those ruling last week.

Coal and Coke.-Coal is strong. Bunker and coking coal are very firm. Gas coal shows no change. House· hold coal somewhat dull. Coke continues in excellenb request, and a. verage blast-furnace qualities delivered here over the next half-year are fully 28s. 6d.

Bolcko1o, Vaughan, and Co.'s Shares.-Formal nonce has been sent out of an extraordinary general meeting of Bolckow, V a.ugha.n, and Co., Limited, at which a pro· posa.l to split the shares will be made. The proposal IS to divide the present shares into 20 parts. The total capital of the company will not be affected, nor the voting ~wer, nor the liability. The effect will be simply to div1de the stock into what some holders believe to be more saleable parcels.

NOTES FROM THE SOUTH-WEST. Ca.rdi.tf.-Busin~s in steam coal has been somewhab

interrupted by the Easter holidays; prices have! h_ow­ever, been maintained with firmness, the best descnpt~~ns making 22a. 6d. to 233. per ton, while secondary qualities have brought 19s. to 20s. p~r ton. House coal ha.s shown little change ; No. 3 Rhondda large has been quoted at 22s. to 23s. per ton. Coke has also made about former terms, good foundry qua.litieo being priced at 32$. to 333 per ton; and furnace d1tto at 30s. to 3ls. per ton. As regards iron ore, the best rubio has been making 20s. to 20s. 6d. per ton.

South W ales Coal CliT1.d I ron.-The total shipments of coal (foreign and coastwise) from Ca.rdiff1 Newport, Swansea, Llanelly, and Port Talbot, in Marco, amoun~d to 2,106,180 tons, as compared with 2,103,399 ~ns 1a ~!arch 1899. The total of 210,618 tons, representmg the shipm~nts of March this year, ~as made up as fo1lows: Foreign, 1, 712,33! tons; coastwiSe, 393,846 t~ns. The exports of iron and steel from the five ports m March were 7100 tons ; of coke, 11,164 . tons; and of patent fuel, 91,331 tons. The aggregate shtpments of ~al from th~ five P2rts in the first three months of thiS year were. Ca.rd1ff 4103 324 tons; Newport, 3,729,074 tons; Swa.d sea, 573)190 , tons ; Port Tal bot, 119, ~l3 tons; ~n Lla.nelly, 61,640 tons. The aggregate sb1pments of 1ro~ and steel were: Cardiff, 8065 tons; NewpoLrb, 602

113 to~,

Swansea., 186 tons; Port Tal bot, 'flit,· and lane y, n : Of coke : Cardiff, 19,549 tons ; New-port, 60!H to~, Swansea, 4152 tons; ~orb Ta.lbot, nil,· and Llanelly, ~ Of patent fuel : Cardiff, 104,956 tons ; Newpor\ 26, d tons; Swansea, 111,254 tons; Port Talbot, 'fl~ ; an Llauelly, nil.

Th-e Porthkerry Viculuct.-The_restoration of ~be Por~: kerry Viaduct on the Vale of Glamorgan Railwdy, tb tween Ba.rry ~nd Bridgend, was com{>leted un. er f direction of Mr. J . Bell, C.E ., the res1dent en~e~r 0

the Barry Railway Company, about three ~ont. 81~:. and heavy mineral traffic has been run over 1t daily . d since. Last week a. Board of Trade inspector examtneo. the work and certified the structure for passenger trafti

, f The South Wales Coalfield·-¥r · T · L. . Re~ the

Ca.eran, Maesteg in some pa.rt1culars r~la.tmg be a _ South Wales coalfield, sa.ys the extent ofillt m~the nefd proximately estimated at 1000_ squ~re m es. an Moo­extends into parts of five counttes, VIZ. , Glamo~ ' tesb mouth, Brecon, Carmarthen, and Pembro~b B~~Bay length is from Abersychan on th~ east to · breadth is on the west-89 miles; and t ts greatest 1 . be· 21 miles in Glamorganshire. . The tota a.rea. sed neath th~ sea. is 153 square miles_; t~e area edx~ith is 845 square miles, and one mile 18 cov: on the · newer formations. The coal measuBes r:&e Millstone Millstone Grit, but west of Swansea. ay the Mono­Grit d~a.ppea.rs, an? the coal measures rest U~rian. The tain Ltmestone ; sttll fu~ther west,. 0~ the 8

220 ft .. it is total thickness of t~e Millstone Grllt R a~o:ftl the d~tricb. often confounded wtth the Fa.rewe Moc ta'n Limestone Between the Millatone Grit and the .oun. 1found The a. mop of conglomerate about 20 ft .. thick J.S d to ~abou~ total thickness of the coal measures lB assume

APRiL 20, 1900.] a

7000 ft ., and is divided into three series, v~z. , the Upper Pennant, the Lower Pennant, and the \Vhtte Ash.

Ntto Second-Class Cruiser. - f'he chief engineer of D von rt Dookya.rd has been mformed that Keyham F:otorf will be entr~sted wi~h t he manufa-cture of two sets of triple-expanston. engmes, ~.set of w~ter-tube boile~t~ and several port1ons of auxiliary ma.chmery for

new "~eoond-class cruiser which is shortly to be laid down :t Devon port. The designs have n? t yet _been cO?lJ?lete~, but it is understood that the ormser _w11l ~e stmllar m b ild and armament to the Bermes, m whtch ca.se her e~gines will develop collectively 10,000 indicated horse-

war. Her machmery will t?e put in ban~ immediately fbe working l'a.tterns are. rece1ved ; they w1ll be the most powerful engmes ever built at Devonport.

Netoport Harbour Board.-A monthly meeting of the New or t Harbour Board was held at the offices on W ed­nesd~y. The Dredging Committee rec<?mmended that the dredsing plant s~ould resume w<;>rkmg at Powder­house Pomt in May, m accordance w1th th~ recommen­dation of the harbour master. Mr. J. Davtes (represen­tative of the pilots) moved as a.n amendmen~ that the dredging be deferred f~r two mont~s. He sa.td ~e had made low-water inapect10ns of the r1ver a.t the pom t a.nd found that the accretions had accumulated during the three months. H e ventured to ~ay that if there . had been no dredging at all, the pomt would be preciSely the same as now. The dredging operations cost last year 2000l. , and as the work bad been of no use the money had been virtually thrown away-. Mr. Alderman Moses a.sked Mr. Da.vi~ why b~ dtd not make his statement to the dredgmg commtttee, of which be was. a. me~ber, and wbi~h be a.ttend~d. Mr Davies said 1t wa.s smce the meetmg of the com­mittee that be had come to a definite conclusion on the matter. The harbour master said he was of opinion that the dredging bad do~e good. It wa~ true there had been a little silting UI? smce the dredgmg of last summer ceased but the l>Omt was clearer than it was before there wa.s a~y dredgmg; and with?ut dre?ging at all, Mr. Vernon Harcourt, the consultmg engmeer, had warned him that the bank would increase, and might even stretch from one side of the river to the other. It was decided to renew the dredging May 1.

GRAPHIO METHOD OF BALANOING MARINE ENGINES : EBRATUM.-We are o.sked to make the following errata, in Mr. Macfarlane G ray's article, published on page 487 of our last issue : In column 2, line 6, from bottom, C C should be 0' D ' , and in column 3, line 25, from top, E 44 should beE 44', and in the last equation given in that column F4- F L should be - F4' + F L. There should be a K ~n the lowest line of Fig. 3.

SwEDEN AND NoRWAY.-Tbe Swedish a.nd Norwegian Governments are constructing a railway from Gellivara to Ofoten, on the Atlantic Ocean. The line is making rapid progress, and is expected to be coir!pleted m 1902. Important deposits of ironstone a.t Ktirunavaa.ra a.nd Luossavaa.ra., belonging to the Gelliva.ra. Mines Company, will become available for more general consumption upon the completion of the new line.

BELGIAN BLAST·FURNAORS.-The number of blast-fur­naces in activity in Belgiuru at the commence ment of March was 34, while G furnaces were out of blast a.t the same date. The total of 34 was made up a.s follows : Cbarleroi group, 14; Liege group, 14; and Luxembourg, 6. The production of pig in Belgium in January was 89,880 tons, as compared wi~h 105,820 tons in February, 1899. The aggregate eutput for the firs t two months of this year was 189,390 tons, as compared with 190,190 tons in the corresponding period of 1899.

AoADElllOALDRGRBE CoNE'ERRED ON MR. ROB'BRT GATRD, SRLPBOILDEB.-We offer our congratulations to ~Ir. R obert Caird on the honour conferred upon him on Tuesday, the 17th inst., by the University of Glasgow, when Professor Moir !?resented him for the honorary degree of Doctor of Laws m the following terms: Robert Ca.ird, shipbuilder, Greenock, a. member of the firm of Gaird and Go., F ellow of tb~ Royal Society of Edinburgh, President of the In· stitution of Engineers and Shipbuilders of Scotland.­Mr. Caird is well known as a leader in the great industry which has made the W est of Scotland famous, and his eminence as a. shipbuilder has already won for him the gold medal of the Institution of E ngineers a.nd Ship­builders in Scotland and the presidentship of that im­portant bodr. T be U niversity, which possesses the only Britisb Chatr of Naval Architecture, may well a~ociate ~erself with the Royal Society of E dinburgh in mark­mg. her appreciation of Mr. Caird's valuable contri­butions to this branch of applied science. And we cannot keep out of view the interest which Mr. Ga.ird has dis­played in the present movement for the improveman11 and extension of the scientific aide of the Umversity. And Mr. Caird is not merely a. practical ma.n. F ollowing the early tradition of Scots students, Mr. Ga.ird completed on the Continent the edu~ation he began here. In the ~u_ree of several years' residence a.broa.d be aoquired an 10t1m~te and extensive acquaintance with the language and hterature of France, Germany, and Italy, a.nd he ~as also privileged to carry on important investigations

MID the domain of history and art under the direction of

r. ;Rusk~n. His labours in this department were re­co0 gnlSed m 1895, when be was created a Knight of the

rown of Italy. His papers, lectures, a.nd addrel!ses on th~ aubj~~ in which he is in terested display not merely solid erudttion, but marked literary charm. On all these grounds I have to ask you to add Mr. Gaird's name to our roll of honorary graduates~

•

-E N G I N E E R ·l N G. . -

MISCELLA.~EA. T wo years ago, two cars covered with copper, ins tead

of being painted, were put to run on the- New Haven Railroad a.s an experiment . The copper wa~ simply allowed to tarnish, a.nd has, it is stated, a good effect. Neither oa.r , we learn, has cost a penny for outside repairs from the start.

From ret urns p repared for Rylancl!s Iron Trade Circular it appears that the number of blast-furnaces in blast on March 31la~t was 404 out of a total of 605. This is an increase of three in t he number in blast whilst the total number of furnaces standing is one less than a.t the end of the previous quarter.

The world's record for turning out steel rails was again broken a.t the plant of the lllinois Steel Company on March 22 last, when the day shift put out 1442 tons in 12 hours. The previous record for 12 hours wa.s 1391 tons. Following the breaking of the world's record the night-shift turned out 1235 tons, making a total for 24 honrs of 2677 tons. During the 24 hours the rolls were shut down 1 hour and 57 minutes

The g reat strike of engineers' machinists at Chicago, which threatened to spread throughou~ the whole of the U nited States, has been settled a.t a conference between the union officials and the employers. The basis of the agreement constitutes a. victory for the men, a.t least so fa.r as the length of the working day a.nd the ra te of wages is concerned; bub the reports at present to band give no information as to whether the cla.i m for the exclusive employment of unionis t labour, and the coneequent ex­pulsion of freemen, has been acceded to. The nine-hours day is, however, to be granted, and this concessien seems a. perfectly reasonable ene in view of the fa.c~ that it has been the standard in this coun t ry for close on thirty years.

The Administration of the State railways in Russia. has prepared for the the Paris Exhibi tion a. notice which con· tains some interesting particulars as to the progress made in the last 10 years. In 1890 the total length of all the railways in Russia wa.s 18,310 miles, a. fourth of which be· longed to the State, the remainder being didtributed over 42 difterent compa.niell. On January 11 this year the total length of hnes open for traffic, exclusive of light district railways, was 28,365 miles, of which 9205 mHes belonged to nine private companies and the rest to the State. The State railways a re divided, for admini­strative purposes, into 22 companies, each of which has its separate mana~ement, a.nd about 3800 miles are in Asiatic R ussia. 'I he State ra il ways possess 1380 loco­motives for passenger trains, 6060 for goods trains, and 9050 carriages for passengers, 169,400 trucks a.nd goods wagons, a.nd in 1898 tbe total number of trains was 1,362,056, which conveyed 511492,000 passengers of all classes, travelling a.n average aistance of 80 miles. The gross receipts of the State railways were over 327,000,000 roubles, and the working expenses 195,000,000 roubles, leaving a. net profit of 132,000,000 roubles.

The N ew Zealand Governmen t has just published correspondence with the E steve Steel Company, regard­ing the outcome of experiments made by the company in the utilisation of the iron sand of New Zealand. Although the experiments had not been so full or so com· plete a.s was desired, the st eel company declare the tria.Js to have been successful, as they had succeeded in making high-class tool steel in the crucible direct from New Zealand sand. They find no difficulty by their prpcess in eliminating the titanic acid a.nd other imJ_>urities. Nearly the whole of the metal in the sand is utihsed, and t he process of con­versioB occupies about three hours. The steel produced, they declare, compares favourably with the best Sheffield brands of crueible steel, and is made a.t a. price consider­ably lower, a.s one operation completes the whole process. They have also succeeded in agglomerating the sand by itself, without adding any foreign matter, the lumps being a.s hard as stone. The pig iron produced contams only 0.07 silicon, 0.01 sulphur, 0.03 phosphorus, 0.33 man­ganese, and no titanium. The company have asked t he Government to bear the expense of carrying on some practical exp erimen ts in the agglomeration of the sand a.nd in the making in a. Siemens-Martin furnace of tool steel and soft steel, both from the sand eo agglomerated and from the sand in its natural state.

F or many winters ~a.sb the intake pipes of the water works of Marquette, Lake Superior, have given trouble, through being blocked by ice, so that water famines have been a. frequent winter experience in the town. The origin of the trouble is not surface ice, but " needle" ice; a.nd, in fact, when the surface of the water is frozen, no difficulty occurs. When, however, this surface ice is carried a.wa.y by winds, the same winds prevent fresh ice forming on the exposed surface, and the frozen particles, ins tead of conglomerating to form a. continuous sheet of ice in the usual wa.y, a.re carried by the eddies below the surface, and thus carried into the intake pipe. This phenomenon is by no means unknown in this country, a.nd only a few years back, the outlets from the reservoirs of one of the L ondon water companies was blocked in a precisely similar manner, during a. comparatively mild winter. It is, however, of very rare occurrence here, a.nd accordingly n o special mea,sures have a.s yet been proposed by E nglish engineers for dealing with such difficolties. A t Ma.rquette, however, the authorities have now applied an electrical heater by means of wh1ch ibis hoped future trouble will be avoided . The heater con­sists simply of a. large iron resistance coil fixed at the pipe inlet. The a pparatus will only be brought into opera­tion as occasion demands, so that the expense should nob be high.

Some important irrigation work iEZ, we learn, about to

- 7

, : be undertaken in the V alley of the Dura.nce, in the ~e­partment of the ~ou~hes ~u Rhone, Fra.n~. The dlS· trict served by th1s nver 1s extremely fertlle, but very liable to drought. The river itsel~ be!ng fed from the A lps, has a. very variable flow, wbtoh m tUDes of fi <?od ma.y amount to 220,000 cubic feet per seco~d, whllst a t other times it may fall as low a.s 1500 oub1c feet ~r second. The.~e periods of low water a.re most frequent m April a.nd in August and S.ep~~m~er, a.nd a.s the normal demand at such periods for trr1g:a.t10n water ts about 2800 cubic feet per second, the defic1t has on ~ore. than one occasion led to a. free fight between the parttes mterested. Suoh outbreaks have, it is true, been cheoked by the passage of bye-laws regulating the respective righf::s of np a.nd down s treamers; but it ha.s also been determmed to remove the source of the disagreement by creating l.arge impounding reservoirs in the upl?er valleys of the nver. Two proposa.Js are under discuss10n, on~ of these r~er­voirs it is suggested, should be situated m a defile a. httle belo~ the confluence of the Uba.ye a.nd the Dura.nce, in the Department of the Hautes A lpes, whilst a. second scheme is for a reservoir a.t Saiute Groix on t he Verdon. The former of these reservoirs would impound 5,650,600,000 QU bic feet by means of a. dam 147~ ft. h1gh. The water area of the lake formed would be 185S' acres, a.nd the oost is esti­mated at 430,000l. The Sainte Groix reservoir would con­te.in 4,591,000,000 oubic feet, the dam being in this case 98ft. high, and the estimated cost315,060l. Trial pits and borings are now being sunk a.t both of the sites under discussion, with a view to ascertaining the eha.racter of the founda­\ion accessible in either oase. During the winter floods ~he mountain torrents which feed the Dura.nce bring 4iown very heavy bonlders, which will tend to fill up the reservoirs, and prehmina.ry studies are now being made as to the best method of meeting this difficulty.

The German Society of M echanical E ngineers will this year award the Veitmeyer prize of 1200 marks with gold mEdal, for the best plan and specifications for a.n electric railroad between two distant cities, designed exclusively for trains running a.t a. sp eed of 200 kilometres (124! miles) per hour, a.nd following each other in quick succession without intermediate stopping points, each tra in to have a minimum capacity of 150pa.ssengers. The s tipulations are given in full in the J a.nua.ry number of Glaser's Annalen. and the con test will clos~ on October 6 this year. The prize will be awarded a.t the November meet· m~ of the society. Concerning the subject selected, Mr. Wtchert, one of the prize judges and a leading German Government engineer, writes as follows : "The problem ha.s a special int erest a.t the present time, as the new cen· tury now dawning ma.y see its practical solution. The con­struction of ratlroads specially designed for light trains of high frequency and enormous speed ha.s so far received only passing attention. L ook a.t it as you will, it is in line with the progress of the times; but whether a. prac­tical solution is possible or not, time, study, and ex­periments alone oa.n demonstrate. The subject! requires that careful consideration be given to the d esigns of terminals with the neceseary installations for handling trains of 200 kilometres' speed without risk or con· fus ion. As such speeds have never yet been attained, the problem may bring out the impossibilities.t if any, which stand in the wa.y of solving 1t. No detmite distances being laid down, the solution will not give absolute, but only relative quantities. Correct theories ought to be de ve­loped in regard to the resistance a.t high speeds, which in the U nited S tates have already reached 150 kilometres per hour. The problem must, therefore, be based on an unprejudiced review of the literature and the material at ha nd in such matters a.s train a.nd a.ir resis tance, brake action, &c., referred to high speeds; a.nd the committee having the subject in charge thinks that there is still a wide field unexplored in that direction."

BRITISH CoAr. IN GERMANY.-The imports of British coal into Germany last year were 4,873,555 tons, a.s compared with 4,506,163 tons in 1898, and 4,808, 900 tons in 1807. It will be seen that the imports increased last year to the extent of 366,392 tons.

SMITH's SPIRAL SLim~ RuLE.-A spiral slide rule of & novel design, due to Professor W. H . Smith, is n ow being introduced by Messrs. J. H. Steward, of 406, Strand, L ondon, W.G. The instrument ha.s a scale 50 in. long, enabling calculations to be made with certainty to three significant figures, whilst itl is possible to estimate a fourth figure by means of the eye. The spiral scale is placed round a cylinder, over which slidee a. metal tulx>, have wide slots, through which the scale below oa.n be seen. At oppo~ite t-nds of these s lots are reference marks, exactly the length of the scale apa.r b. A cursor provided wit h other reference marks ~lides on this sleeve. To effect a multiplication, for msta.nce, one of the reference marks on the sleeve is brought opposite one of the factors on the scale; the cursor is then moved opposite one of the ends of the scale in which condition the distance between the referenc~ mark or the cursor and the reference mark on the sleeve is proportional to the logarithm of the faotor aforesaid. If, now, the sleeve is moved, carrying with it the cursor until the reference mark on the latter is brought opposi~ the second factor on the scale, the product can be read off against the reference mark on t he sleeve. With the excep­tion of the scale, the whole of the instrument is constructed of metal heavily n ickel pla.ted, so that all danger of the sticking.in damp we~ther is avoided. The ~rra.ngementJ of the Instrument Is such that a oa.lcula.t1on is never br?ugbt to a. stop as occasionally happens with other sptral rules by part of the scale required being hidden by a portion of the instrument. The dimensions of this new calculated rule are small, its length being bu~ 10 in and its extreme diameter over the cursor M in. .,

•

•

,

•

I

•

•

•

•

•

E N G I N E E R I N G. [APRIL 20 , 1900.

COAL-HANDLING PLANT AT THE WANDSWORTH ELECTRIC LIGHTING STATION. CONSTRUCTED BY ~lE RS. GRAHA~I, ~IORTON, AND CO., Lll\IITED, ENGINEERS, LEED .

(For Descri1Jtion, see Page 624.)

•

Fig. 4 .

--- ---------3· ~~-------------1

·---h.,,........,,r---------,.,........,,..;· :::::: ~IX~, rt---=~IX:e I '8j-: -:;:, . J. ·?Z. - -<4 .. , ..

I I 11 I I I I I I 11 I I I 1 I I •

1 11 I: .I \ it..- ' .. .... _J'.

'-.r~ll~- --- 1 ~--- - - .. rt..oo:-;::oJ PU41oplou F<'"'eyor

~~~~~~ .. ~15 .. ~.,,~,~~ ~-~--~.F~~-~r~ .• ~.====~======~~~~~ ~ _ : '"' ·---., ,. -A'~ ~,--- - Z3~ -t~~~

j , . \

~'~ r----11- -lt-1- - t- ' ' • ~ wut+ .... ...., .. ~~~ ' > P, lt - t- . - · 1- . t- 1'-rH·

· ~~ . ~~ _ r tu 1\ , ,~

4

~~ ' b -..,

_') -~

'Cl; ·l \ "" • -~ ;:,

I

V 1 \ : ~·~v , ~ I ., , u .. 1 r----- ·.2 ' Sf.--- ---- 7 1iJ',· t··

---- ---- -- 4: ~1:i·-- -------~ ~-

\ ~" ) 1 Wo."""- ' P. DlOJ. d.o!Wu thrca.. ~

'- ../ 7'f•P. to• tJ ..,_S.:l'Borc <;> '

.......... _,. -----, , ,

I I \ I I

' I I I I I I

V

0

C::::~!:~~~~~~J2~3~~~3=·A~l:· ~~l~3J------~~~~~~~ ~J... ----1'8J;a'--- -r------.z· ov-----~ · -8,.--~~ S,4fiR.S.JS'·S ~ ' Lo:l - ~ .- \.

~ .L__ - --

' I ... c:~ll~ ..

.Fig . 7.

-·----------

I

I I

Fig .8 .

' ' \ ' I

~ \

I

~ 'C) . . - j l

\ \

' ' \

)

If

I •

/ /

- - ·--. -•

•

"vi pur Wh.u.L s: or,, P. nt.-OJ • 6 '~ace, :Z '/iPi.tc~, 4'Bore. 84 T~

~ I .Fig .5 . i

•

•

\ •

\ ~F==

"· ~ ~

' I I

Jt q:) .

1 ,--+-- ....... f

o :o ................. Srru.rPJnir~. .., _ ";-: ! ~~ l'T o 'F.'" .z14P. 4 •• • r _1 .J. 1: , I

3: Ofi Worm, to s rill r. nu.'L1 .\ I \..,. 1/J f - -;-- l: l : t.Jv.eo.<L wor~n~ d v· 1 'riP. i 'Jl L~ 1L !: : l

-· ~' 10h·-- -------- - 'll ' 1l ·----1 .. lt I 1

:1·1 - - ----( ------- ~ - .:"'\ : (T ·--1--=~·-----}--· ] .l '·: :; ~- ~ . , .. , -· r~-:j --z· ":.7:__1 ~ CO : • :: ) . -:-: - r. - ?<:, ~ I' ' ':'~ ~~-- --- l~ 11 .... 11 I ; -~ ::1 l ,1 1 1 "\ '-T--.-J I I

1: ':1 ~ ~C.,. ,,.r;, . ,.,_, .. v6·~- -~- l~ t ;: ~ .. -, ·~·p 10' t.ur.s : I : 11 . .. .J ·: ·~ ":' ... ....... 12 '~ ~ :z ?-~ l.c1tfJ·

.: l ~ L -1 ' -- ji 11 I

- - - I I I ~: --- -~ t;'l . ,,. 1.1~·--- l 6•3'ChArt): 6' ?'l.A l' I

o --- !.: j:::-------- - - ---- --~· s_------------- --------- ~:.! 4 : S'.4~ l '? S". 4 "T ''1 1

Fig .6 .

• 11 IJ

:·1.: ' ~~,... I • I \J't

I 1 0 •

........... I •

I ! I I ~ , ' IQ

•

I I

I I I I I I I I

I I

i.'l \1) .. ~,

I N I ~ I I I I I I I

I I I

IQ I

* ~ \ - r·r-I ---I

3' tf-' ..... . -

I

' I 4' ,- --I I - -(; 2·---I

-s:sfi -------

\ \

' ' ' \ ' ' \ ' ' \ •

\

' \ ' \ \ ~-

·8 F t9. 10.

' ' ' \ t!loU. n. 'bolJ, or ,, ,, ,, o I

u

'o ... . ~ I

I • q:) . c;-1 I I I I

' I « . CO

f I I

' I I I I

't.b -. q)

I

' I I

' I I

' I I I I -· --1 I I I

I •

. ~

• !:" ~

...., (

~ ·t 4 S ;; s 0') 1

I • V')

, .....,. ~"\ . _"t_-

•

- -- -;z.s: 2·- - -

• ~

CO

< 0 0

I ~

I I

~ I •

l:o ;_\IQ

0 •

~ + .....

• ~0 -I I ... .1 1 o .

* • • • C' -~----------------------1

0 1 ~- - -·1 : t>---..1 . ~. .£rrect.We c'¥1~ or flapper 50Cu1J.F!'

- ~ ----------------1 -'· <t-_ • 1 T01t1 or CoUJJ. c 1< - r. o -

' .e

' \ ' \

•

\ \ \

• 11) -

I I

I -~-

Fig 9. ..

__ .....,

•

I

•

0 I

• • I'

~ •

: I

j C:::.

; ~ 0 0

• • I • •

' 0

•

I o I

•

TI-IE LANGE l\ IONO-RAIL SUSPENDED RAILvVAY AT E LBERF}-:LD-B ARl\IIEN.

(For Desc1-iption, sPe Page 501.)

F10 . 14.

~lfr,<flltqlt ' " }j,.(IKI' . • • IB\ .1· =·

"';~ ;:;- ~ ~~- "~ ~ . '\

I ~ .Ftq 76 ' . 1: ~ - ~il '

Crn.l.r<\.< or J3 OCI' t-A t; I I 7 -.J //

~ ~. "1 .:.~ ·- ~ ~\ . ~--· .. :fL. • ··------ -------· ----· ---.--...... -- ................. _____ ___ .,. __ ----·- 8•roo ... .. -· ... -' 1:. ;,so + !.$(.

- ' ... • • . I • •

..C.~ so~ ;. J{IQ() >I

~ ·- --------· .. ..... . -- ----- -- - .... --- ....,_ .. - ---·- ··-- - .... .o.c----------·- ·------- ---.. ...

• -~

... .. --- - Q (/ 11· - . . ~ /l(lJ[J

• Huller w<tJt Au.to Cr "·~ f ' "' :it F ;;ii:

'r ~ I ,1 ,-·"!=-=~:· ~

:'.: ·' I' ;- ·

~ i: : ~-. ~ '~ ·r··y· i . ~ ... ----. . ) • • • • • .

~ · • • • . I t I ,.,. . • ~2'1 8911 7.'111

~JJ. •

• •

'~ ll'l? • ')<#12 •

• . I

/} • , !I I f I (/ .I ., 11 H

\ -·~: · ~,)l -;;-.. _ •

~

-~- -. ru·~ • •

J~, • ~ f • ::, ... .. . ~

~?O 1~ I • : \ I • ll·ll .

• 12,7~ "' • 7•'lH • · ·M7 • ~ ---t '1600

' • .. -- ' if, • • • • I • • ~1 I I

I • 1 ~ ~

J ·!.4 -;;..;;;; ~ .. ·-'!¥. • - ·' !-:-'.~·· ~

• . .. ' • •

7$0

...... . ..... ... ... ··--- -

/

I I

I

-----·--- --·

. . ________ .,. 2586 ·--······-·

----- --- ·-----------1 -- 41176 ..... --·

.. ··- ... - t--+---i

'Z3

/ ~~:~ -·- -:-:--·- -·- - ---- -:=:::::.:==='!-

•

'J • • I I • •

-~--

•

TootJud

r·

892-i .• J., : I I •

! I i 0 I • 0

• 0

I I

I I 1

I

l f)(JQ /)50

•

Fif1.77.

Fig.18.

• . • 0 I

~ ~ t ... ~ - CV , ~.

• • • • I o I • • 0 I

• • • 1 o

• 0 0

0 :n ,-'

· --·506 ..

· l---!----1·· . --- ....... - --- ·!--+--+

•

f.i'ig. 19.

r----- 7ll0· . ..1

n 'ISO ··- -----·

- - --- .

............ ···1----1

..

1

~ ·

I

I

•

F IG. 15.

/

/I -~ I ~ '-\ 1/ ,. ,.,..~ ~ ~ \\ ~I w N ,. IJ

r '\ I '-i ~ \~~ --1-

I I _,.(~ ·-·--··-···--·----··- ---···-- . ~ \ I ] ' I • -''1~. .... - • 'r(}(l .. I· r ..

Q()('(l . . -------------- '>i

tW . ~.

'1 ~ k:: --'1JJ ~ ;if - -CPI.lp/irtg.RI>rl

~-

- ·- ,,

\ l \ I

... - '-- -•

0

' 0 ------------ ---·- ------------- ---------·---~-- --------···-··- ---------·-----., . .. q<XJ()-- • - - --- - .. .. . -4

'-1-

• • • • •

APRIL 20, 1 goo.]

AGENTS FOR "ENGINEERING." AusTRIA, Vienna: Lehmann and Wentzel, KH.rtnerstrasae. OAPB TO\VN : Oordcn and Gotch. EDtNBURGU: John Menzies and Oo., 12, Hanover -street. FRANOB, Paris: Boy"eau and Ohevillet, Librairie Etrnng~re 22

Rue de la Banque; M. Em. Terquem, 31 bla, Boulevard Haussm~nn' Also for Advertisements, Agence Hava.s, 8, Place de la Bourse: (See next column.)

OBRllANY, Berlin : Messrs. A:· Asher and Co., 6, Unter d en Linden. Frankfur~-am-Mam : Me&U"B. G. L . Daube and Oo. (for

Adverttsements). Leipzig: F. A. Brookbaus. Mulhouse : H. Stuckelberger.

GLASGOW : William Love. Im>u, Calcutta: Thacker, Spink, and Co.

Bombay : Thacker and Co., Limited. ITALY : U. Boepli, Milan, and any post office. LIVERPOOL : Mrs. Taylor, Landing Stage. !JbNORBSTER : J ohn Heywood, 143, Deansgate. NoRWAY, Ohristiania : Cammermeyers Boghandel, Oarl Johans

Gade, 41 and 43. NBW SoUTH W ALI18, Sydney : Turner and H enderson, 16 .nd 18,

Hunter-street. Gordon and Gotch1 George·street. QUBBNSLA.ND ~OOTU), Brisbane : Goraon and Gotoh.

r OR.TB), Townsville : T. Willmett and Oo. Ro'I'I11RDAH : . A. Kra.mer and Son. SOOTB AUSTRALIA, Adelaide: W. 0. Rigby. UNITBD STATES, New York: W. H. Wiley, 48, East 19th-street.

Chicago : H. V. Bolmes, 44, Lakeside Building. VH7I'OR.IA1 Melbourne : Melville, Mullen, and Slade, 261/264, Collins­

street. Gordon and Gotch, Limited, Queen-street.

We be~ to announce that American Subscriptions to ENGINBRRING may now be addressed either direc t to the Publisher, Mr. C. R. J oHNSON, at the offices of this Journal, Nos. 35 and 36, Bedford­street, Strand, London, W.C., or to our accredited Agents for the United States, Mr. W. H. WlLBV, 43, East 19th-street, New York, and Mr. H . V. HoLMEB, 4-4, La.keside Building, Chicago. The prices of subscription (payable in advance) for one year a re : For thin (foreign) paper edition, ll. 16s. od. ; for thick (ordinary) paper edition, 2l. Os. 6d. ; or if remitted to Agents, 9 dollars for thin and 10 dollars for thick.

AMERICAN ADVERTISERS can obtain tull particulars con­cerning our Advertisement Rates from Mr. Wn.LARD 0. TYLBR, 918, Morton Building, New York ; and Mr. H. V. HOLMM, 44, Lakeside Building, Chicago.

ADVERTISEMENTS. The oharge for advertisements is thr('e shillinp for the first

tour lines or under, and eightpence for each addit1onal line. The line averages seven words. Payment must accompany all orders for single adver tisements, otherwise their insertion cannot be guaranteed. Terms for displayed advertisements on the wrapper and on the inside pages may be obtained on application. Serial advertisements will be inserted with all practicable regularity, but absolute regularity cannot be guaranteed.

Advertisements intended for Insertion lD the cur­rent week's issue must be delivered not later than 5 p.m. on Thursday. In consequence of the necessity for going to press early with a portion of the edition, alterations for standing Advertisements should be received not later than 1 p.m. on Wednesday after· noon in each week.

SUBSCRIPTIONS, HOME AND FOREIGN.

ENGINEERING can be supplied, direct from the Publisher, post free for twelve months, at the following rates, pe.yable in advance:-

For the United Kingdom • • • . . .. .. .. • £t 9 2 , all places abroad :-

Thin paper copies. . . • . . . . • • £ t t 6 0 Thick , • . . . . . . . . . . . £2 0 6

All accounts a re payable to "ENGINEERING," Limited. Obeques should be c rossed " Union Bank, Obaring C ross Branch."

Post Office Orders payable at Bedlord-street, Strand, W.O. When foreign Subscriptions are sent by Post Office Orders,

advice should be sent to the Publisher . Foreign and Colonial Subsc ribers receiving incomplete copies

through newsagents are requested to communicate the fact to the Publisher, together with the agent's name and address.

Oflice for Publication and Advertisements, Nos. S5 and 86, Bedford-street, Strand, London, w.c.

•

E N G I N E E R I N G.

NOTICE TO CONTINENTAL ADVERTISERS. -Advertisements from Germany should now be sent through Me,.srs. G. L. Daube and Co., Frankfurt.am· Main, who have been appolnted our Sole Agents for that country for Trade displayed Advertisements. Advertisements from France, Belgium, and Bol· land should be sent through the Agence Bavas, 8, Place de la Bourse, Paris, our Sole Agents for those countries for atmnar Advertisements.

'

REA-DING 0A.SBB. - Reading cases for containing twenty-six numbers of ENGilml!RING may be had of the Publisher or of any newsa-gent. Price 6s. each.

NOTICES OF MEETINGS. lN~TlTOTION . OP Orvl:L ~GIN~ERS.-Monday, Apr il23, at 8 p.m.,

Spec1al. ~;neetmg. The etghth "James Forrest" Lecture, by Str Willu~m H. Preece, K.C.B., F .R.S., Past·President Inst. 0.-E. ~ubJ,ect: "On the Relations between Electricity anc\ En-gmeenng. The lec ture will be repeated on Tuesday, April 24 at 4.o'clock, for the benefit of members and their friends. Tuesday: Apnl 24, at8 p.m.- Annual general meeting of corporate mem­bers OJ?lY, to rec~1ve the repor t of the Council, and to elect the Council and audttors for the ensuing year.

TuE lN!lTITUTION OF M.BOIIANIOAL ENGJ.NE»RS.-Thursday, April26. The. ch~,1r will be taken at 8 o'clock. Paper : "Road Loco· mott.on, by Professor H. S. Hele-Sbaw, LL.D., F.R.S. Member of LIVerpool. ' ' O~E:ELAND lNSTIT~TION .oF ENGINEERS. - Monday even~g,

Aprtl .. 3, . at 7 .3~ preot€e}y, m the Hall of the Cleveland Literary and Phtlo,~ophtcal S~tet~, Corporation - ~oad, Middlesbrough. Paper on Eleotrolytto Ztnc as a P roteot1ve Coating for Iron and Steel," by Mr. Sherard Oowper -Coles, Westminster.

T HE I.NSTITUTIO~ OF ELECTRICA~ EN_GINBBRS .. -:Thursday, April26, at 8 P:m., meett?g. at t h e Inst1tut10n of Otv1l Engineers. •' The Electrto TranSIDlSSIOn of Power," by Professor George Forbes F.R.S., Member. '

RoYAL I.NSTITOTION OF GRRAT BRITAIN.-Friday, April 27, at 9 o'olook, The R i({ht Hon. Lord Kelvin, G.O.V.O. D.O.L., LL.D., F .. R.S., M.R.I., on " Nineteenth Century Clouds over the Dy.na­tDlcal Theory of Heat and Light." Afternoon lectures next week at 3 o'clock. On Tuesday, April 241 Mr. Bug h. Rober t Mill: D.So. , LL.D., F.R.S.E , on "Stud1es in British Geography" (Lecture I.). On Thursday, April 26, Professor Dewar, M.A., LL.J?., If·R;~·· M.R.I., on "A Century of Chemistry in the Royal Instttut10n (Lecture I.). On Saturday, April 2g! Professor Stanley Lnne· Poole, M. A., on " Egypt in the Miadle Ages" (Lecture I .).

THE INSTI...,..TO,_T'ION OF ELBOTRIOAL ENGINEBRB : STUDENTS' SECTION. -Wednesday, Apr il 26, at 7.30 p .m. A paper will be read by Mr . Bumphreys (Student), on "Magnets and Motors."

T l.rB I N.STITUTION OF MINING AND METALLURGY. - Wednesday, Apr1l 25, m th e Lec ture Hall of the Geological Museum Jermyn· street, S .W., at 8 o'clock. To read and discuss the 'following papers : I. " The Electrical P recipitation of Gold on Amalga· mated Copper Plates," by Dr . T. Kirke Rose, M. Inst. M.M. II. "Notes on the Namaqualand Copper Distr ict," by Mr. J. A. Chalmers, M. Inst. M.M. Ill. "A Note on Band Concentration Tests," by Mr. Waiter McDermott, M. Inst. M . .M. IV. "Notes on the Elmore Concentrating P roceps," by Mr. 0 . M. Rolker, M. Inst. M.M.

ENGINEERING. FRIDAY, APRIL 20, 1900.

AN EXPORT DUTY ON COAL. THE question of an export duty on coal has been

raised in Padiament, aud is to be again brought before that body. This is a matt~r which comes to the front at intervals, especially when trade is good. We remember that it was warmly debated during t he coal famine which followed the Franco-German War, and many manufacturers were enthusiastic

We desire to can the attention of our readers to in their support of the proposal that a tax should the fact that the above is our SOI·E Address, and be levied on all coal which left t he kingdom. At that no connection exists between this Journal and that time the price of household fuel rose to 50s. any other publications bearing somewhat stmnar per ton in London, and the poor suffered greatly titles.

1 in consequence. Even in middle -class house-

TBLBGJu.Pmo ADD.u.ss-ENGINEBRING, LONDON. holds the increased price was painfully felt ; and TBLB.PBONB Nt1l{BBR-8668 GePrard. Punch took advantage of the occasion to depict Mrs.

-==:.=::::=================-==--:===- J ones giving a '' fire party," at which her friends CONTENTS. enjoyed the unusual luxury of baskirig in the beams

PAGB PAeB of a thoroughly good fire. At t he same time manu-The Des ign of Rotary Con- Coal - Handling Plant at facturers found their coal bills increasing to an un-

verters (fllmtratld) .. .• 499 the Wandswor th Electr ic fi hil h 1 h t The Langen Mono-Rail Sus· Lighting Station (Rlm.) 524 heard-of gure, w e t e supp y was very s or .

pended Railway at Elber - Notes from the United even at the enhanced prices. Colliers' wages rose feld-Barmen (Jllmtrated) 501 States . . ...... . . · · · · · · · · 52! immensely, and as their remuneration increased

Modern Field Artillery (n- T~~ GEenngeinrales of Bt~eq~ed'::~~ their working hours diminished, until the pit-owners lmtrate.d) . . . . . . . . . . . .. . 603 The Institution of Naval (IUustrated) ..... ... .. · · 626 were in despair. The morning papers contained

Architects (fllustrated) .. 603 On Aerial Locomotion ... · 526 picturesque descriptions of miners drinking cham-Notes from the Yorth ...... 614 Railway Constructions in d f h · vill ~otes from South Yorkshire 614 New South Wales and pagne-or what passe or c ampagne-m age ~ J~~~e~e;J~::OO:es ~~ 514 In~~!~r~i ·No~·:::::::::: ~~~ p~blic-hhou1ses, 1abndtcfheeding 1tdheir d

1ogs oint the best

Notes from the South-West 514 On the Influence of DeJ;>t h jomts t e oca u er cou supp Y· was per-Miscellanea . . .......... ... • 616 of Water on the ResiSt- fectly natural t hat there should be an outcry against An E>.1>ort Duty on Coal . . 517 ance of Ships (fllu8.) • · · · 628 letting coal go out of t he country when it was so The Multiplioa.tion of Trusts 618 Turning Moments of Marine The Motor Oar Exhibition .. 519 Engines (Rlmtrattd) ... . 630 badly wanted at home. The Paris International Ex- On Balancing of Steam En- It was not long, however, before a change came

hibition (IUustrated) .... 619 Laguinncebs e(sl~~dtrTra~:f>T;i·p·a :: ~~~ over t he scene. Hundreds of men forsook their Notes ... . ........ ......• • 622 A.U

The Johnson-Lundell Sys- .. Engineering" Patent Re- usual pursuits to become colliers, in the expectat~on temof Electric Traction .. 628 cord (fllmtrated) ... · · · · · 633 of livine: like fightin

0a-cocks. Old unremunerat1ve

The War in South Atrice. • . 62S ..., With a Two·Pa{Ja Bnaraving qr THE LANGEN MONO- mines were reopened by limited companies, a.~d lUlL SUSPENDED RAILW..4.Y AT ELBERP'BLD· sold to confiding investOl'S who looked for _splend1d BARMEN. dividends. Existing collieries had therr roads

•

enlarged, and were fitted with new winding machi: nery. By every possible means t he output was increased, while at the same time the flood of good trade abated, as France and Germany returned to industrial pursuits, the latter with greatly-increased energy, in consequence of the influx of gold paid by the losers as war indemnity. The price of coal fell rapidly, and very soon the margin of profit almost disappeared. It was only the best situated and best managed pits that were really remune­rative, in spite of the large reductions which were made in wages. People talked no longer of an export duty. It would not have reduced home prices, for they were already at t he bottom; while 1t would probably have closed a good many pits, and have rendered employment for colliers more fitful than it already was. The economic side of the question was forced to the front by the general depression of trade. I t was seen t hat coal is a com­modity by which we pay for many of our imports; and that if we send less of it abroad, we shall re­ceive in return less wheat and cotton and wine, and the thousand-and-one necesearies and luxuries which come to us from the foreigner. If our exports of fuel fall off to the extent of ·a million sterling per annum, our imports must decrease correspondingly, or else we must pay for them out of accumulated capital- a spendthrift method whicli cannot continue long. The apparent surplus of our imports over our exports is merely the resul~ of incomplete book-keeping, which takes no note of what is done by Englishm~n beyond their own shores. Nothing is more certain than that, in spite of Government returns to the contrary, we pay in full for all that comes into the kingdom ; and that if we put an artificial restriction on the export of one material, we, at the same time, put an equally effectual stop on many of our imports.

When trade is bad no one proposes the imposi­tion of export duties, however desirable they may be considered in the flush of prosperity, unless-and this is a very important exception-they can be levied without reducing the output. If a tax is to render capital less productive, and to throw work­people out of employment, then it is evidently unjust, unless it presses ~qually on all classes. To single out t he coalowner and the miner to carry an extra sha1·e of the national burden cannot easily be justified. When the coal trade is in the prosper­ous condition which obtains now, these considera­tions have little weight . We could easily use much more coal than we are now doing, and our foreign customers could pay a higher rate than they do at present. But it is doubt ful how long the present good time will la~t. Two or three years is an outside estimate, and then profits on coal will dwindle to the low fi gure t hey have so often stood at in the past. There would t hen arise a howl for relief which no Government could resist, and we should find that we had disturbed a trade without any practical advantage. In a democratic country, fiscal experiments are always attended by danger, and are more likely to lead to loss than gain. The present Budget shows that, however strong a Government may be, it shrinks from trying ex­periments in taxation. The memory of Mr. Lowe's match tax, with ita motto of Ex luce lucceUwm, and later, of t he wheel tax, must bring a shudder to any Chancellor of the Exchequer obliged to find a new source of income.

The advocates of a tax on coal do not, however, found their argument solely on the needs for wider sources of revenue. They have two other pleas, both of them far more weighty than that. Firstly, t hey point out that the possession of ample sup­plies of steam coal of t he highest quality are essen­tial to us as a naval power ; and, secondly, that when our supplies of coal are exhausted, we shall lose a most important factor in our commercial life, and probably the supremacy which we now enjoy. Both these questions are of the .highest import­ance, and either consideration would justify a very serious interference with trading interests. AB regards our Navy, the supply of coal is certainly more important than the type of boilers about which so much interest exists. An inferior boiler with good Welsh coal is preferable for naval purposes, to the best type of boiler with poor coal. All the calculations of t he engineering and constructive departments of the Admiralty as to the speeds of vessels are based on the assump­t ion that the best quality of coal will be used, and if this should fail, the speeds and the radii of action of our ships will be greatly reduced. This would be a very serious matter, and might cause a

I

•

deplorable disaster. It is just this Welsh coal of for coal. In America the tendency is in an oppo­high quality that we are parting with most freely. site direction, and it is more than possible that Out of the 41 million tons of coal exported annually, within ten years America will have a large export about 18 million tons are sent fron1 the four ports trade in coal. of South \Vales. It is not possible to give exact It is not altogether pleasant t o think that some figures as to its destination, but it may safely be day we may draw not only our food, but also our assumed that from half to three-quarters ultimately fuel from abroad. The matter is not, however, of finds its way into the bunkers of British shipping in so much consequence as it at first appears, various parts of the world. A restriction of export provided the supply is cheap. As soon as would, therefore, not only press on the mining the cruisers of a hostile P ower commence scouring interests, but would also affect in a less degree the ocean to snap up our merchant marine, and shipowners, merchants and freighters, in all parts neutral vessels bringing us contraband of war-and of the Empire. coal would certainly be declared contraband-there

Interference with trade is a dangerous weapon will be a sudden check to our manufactures. W e to handle, because it strikes in so many unexpected shall still want to eat, but work will suddenly be­places . Nevertheless, we think that there is good come very scarce. Not to mention the stringency reason to be shown for an inquiry into the probable of the money market, which will paralyse business, amount of the coal deposits in South Wa}es. We our foreign customers will decline to give orders know that this is a subject beset with difficulties, with no certainty of delivery. Even if they are and that the data for estimates are largely hypo- willing to take the chance of delay, they will not thetical. Still, if it could be shown that we are pay the war premiums demanded for insurance. using up our steam coal at a rate which will Our need for coal will diminish at once. H owever see the end of it within a moderate number strong our fleet may be, it will take it months to of years, that would afford reason for the catch all the vessels which will be launched against Government taking steps to guard our resources our commerce, and to effectually police the seas in some way. Probably the best thing for them of the world. As long as we view with corn­to do would be to acquire· a sufficient area of placency our precarious bread supply, it is a work

- carboniferous deposit to supply the needs of the of supererogation to concern ourselves as to what Navy for many years after the existing mines are will befall us if we should ever import our coal. exhausted. Relatively speaking, there is not much Whichever way we look at this question of ex­coal wanted for the Queen's ships, and a long- port duties on coal, it is beset with difficulties. A enduring supply could be easily secured. In case very moderate duty would kill the foreign trade of war, the export of coal would be enormously carried on by the South Yorkshire collieries by way decreased automatically, and the product of the of Hull. That coal has to be sold in competition mines would be immediately available for home with fuel from Belgium, Northern France, and purposes. Germany, and a small difference in price would

The commercial future of the nation is a very turn the scale against it. The Cardiff trade important question, and, at the same time, a very could stand the impoRt better, but it would be im­difficult one. So far as it is connected with the coal possible to discrimina te between different sorts of supply, however, it can be stated fairly simply. coal. There are a number of consumer~ who must Last year we raised 220 million tons of coal, and have South Wales coal, if it is possible to get it. exported 41 million tons, that is, we exported less But many of these, such as foreign navies, are than 19 per cent. of the whole. Supposing by small users, and do not count for much. The taxation we could reduce our exports one-half, then bulk of the burden would fall on our great mail they would stand at about 10 per cent. , and we shipping lines, who are under contract to run at should prolong our period of supply by about the a certain rate, and are obliged by s tress of compe­same amount. Now if we put the time which the tition to go even over that speed. In any case, principal seams will last at the extremely moderate the prolongation of our supplies would not be estimate of 50 years without artificial restriction, attained, except to a limited degree. The redu~­and at 55 years with restrjction, then we see the tion of exports from 20 to 10 per cent. of our utmost gain we should obtain from departing from annual output would not save posterity from what­our traditional policy, and trying a very hazardous ever fate may be in ~tore for them; while, in the experiment which would be sure to work unjustly meantime, it would involve much loss on ourselves. towards large numbers of persons. However 'Ve have the consolation of knowing from experi­serious may be the depletion of our coalfields, it ence that the thing which is prophecied is exactly must be remembered that we are using four-fifths that which does not happen. of the output within the kingdom, and of the re-mainder much is burned by our merchant marine. Posterity may possibly reproach us for our prodi­gality; but it will not have a serious accusation to bring against us on account of our exports.

In the House of Commons, Mr. Balfour said it was probable t hat before our coal was exhausted we should have found some other source of power. That showed a robust faith in science, or a pro­phetic insight, which is denied to most men. Apart from petroleum, the only new sources of power we have heard put forward are the energy of rotation stored in the earth, and the energy of the ether ; but as to how we are to make these supplies available for our uses, no one has given the faintest clue. It is far more probable that our release from the danger overhanging us will come in the way of cheaper transport. The coal deposits of the world have been scarcely touched at present; they are incalculable and pract ically inexhaustible. It needs very little stretch of imaginat ion to see American coal laid down on the quays at Cardiff at a cheaper rate than the South Wales fuel . Cer­tainly that contingency iB far nearer to us than are the new sources of power which are talked of so glibly. Many of our readers. can. remember the time when they would have sm1led Incredulously to be told the wheat of North-West Canada could drive Essex farms out of cultivation ; yet t hey have lived to see it. The American talent for the cheap handling of material amounts to genius. They are now bringing coal to bank at marvellously cheap rates, while the economy of t~eir transporta­tion is a standing mystery to our railway managers. Here the tendency is for the price of all ra. w material to rise, due to stringent legislation in the interests of the workmen and to enhanced wages. We are even discussing an increase of railway rates

THE MULTIPLICATION OF TRUST . HITHERTO the best exemplars of the rage for

combination, which is one of the most significant industrial phenomena of the day in the United Kingdom, have been found in the various branches of textile production. In .America the movement has been amazingly catholic, trusts more or less comprehensive having been formed in almost every conceivable line of activity, from dollypegs and chewing-gum up to the giant steel combine. In some departments of t he iron trade in this country working agreements have been effected, but they have not been impor tant in themselves, though significant enough for the evidence they afford of the spread of the trust principle. It was in textile production t hat the advantages to the manufacturer were first made manifest by the success of the Coats group, and later by the amalgamation of all t he other manufacturers in the same line under the style of the English Sewing Cotton Company. These two con­cerns, working in harmony, afforded a lesson which Lancashire men and Yorkshire men were prompt to appreciate ; and the proper organiser coming along, we were treated to that succession of com­bines to which reference has before been made in t hese columns. The very latest, the British Cotton and Wool Dyers' Association, made its appearance just before Easter ; in a few days more we are promised the prospectuses of a combination in the lace trade, and of another section of t he dyeing trade. But the example is spreading rapidly to other trades. The purchase of the Alquife hema­tite iron mines by t he Millom and A.skam, Consett, and other iron manufacturers is only a partial agreement, but it is worth referring to because it implies recognition of mutual interests, which may

go farther some day when briskness in the iron and steel trade is less marked than it is at present.

An out-and-out combine is that of Fredk. Ley­land and. Co. with the Atlantic Transport Com­pany, whiCh marks a step very much in advance but a natural outcome of, the " rings ,, " confer: ences, " or what you will, which have existed in the English shipping trade for many years past. I t is probable (though negotiations have not been canied very far) that an agreement will shortly be &n· nounce~ betwe~n two. of the large Atlantic pas­senger hnes hav1ng the1r headquarters at Liverpool· and in the South African trade we have of late had the absorption of the Union by the Castle Line. In America there is a pause, perhaps for the reason that, in that pushful country, there are very few firms left to be corn bined ; but still we he<lr now and again of some big schemes carried through even there-the Carnegies, the much-anticipated ''giant steel combine, " and the sheet steel group. We hear of further arrangements among the copper producers, having for their object the complete unification of this industry by the reconciliation of interests which have, down to the present, been inimical to the Amalgamated Copper-Standard Oil group. From Germany comes a report, apparently authorised, pointing to a very important electrical corn hi nation ; France appears to be taking kindly to the craze ; Canada has just seen a woollen combina· tion ; and even the Japanese spinners, although they have lately enjoyed a more than respectable measure of prosperity, are also engineering a cotton· spinning trust, with the express idea of putting up prices, and by united action of forcing Bombay out of the markets of China.

It would be premature to discuss the combine as a world-wide factor in commerce. And, in regard to particular countries, it might be easy to exaggerate the importance of the movement. On the other hand, there is no denying the tendency, and that considerable progress has been made in the United Kingdom is a matter beyond question. When the war is over, and t he British investor shows a greater disposition to meet the wishes of the company promoter, we are certain to have an assortment of combines. Where is it all going to end ? And is it going to be of benefit to trade­not to producers only, but to the whole com· m unity 1

In the abstract we confess to a preference for the old maxim of unfettered enterprise and individual endeavour ; but we can understand that, with the growth of competition abroad and the raising of tariff barriers for the protection of particular co~­tries, the conditions are different from those m vogue a. generation ago. A continuous f~ll in values is not in every way a commendable thmg­it may be carried too far ; and down to t~e last burst of good trade, it was undoubtedly earned too far. An agreement which results in the mainten· ance of values, and serves to impart that strength which comes from unity in face of a . great mena~e, is one that has much to recommend 1t. If Enghsh manufacturers find it no longer possible to _make a living by independent action, they a:e entttled to give combination a trial. Bu~ there ~ alw~ys the inclination to go further than thtB- to ralBe pnces un· duly, when it is found practicable, in order to make up for the long run of bad years when profits come near the vanishing point. I t is too soon to con~emn t~e more recent English combines of abusmg their position but we are afraid there is no doubt that the olde~ concerns have done so; and though ~here is a Nemesis threatening, in the shape of th~ m de· pendent foreigner-who is not ha~pered, m. the English market at least, by heavy 1~p~rt duties­it is in the power of a strong org~rusa.t10n to stave off the inevitable for a long penod, and to work much injury in the mean~ime .. Then the~e has been a aood deal of rnantpula.t10n of capital by promote~ more solicitous for their own pr~tit than for the future of the particular industry wluch they honour with their attention ; and the reader does not need to be reminded, we suppose, ~hat an inflated capitalisation implies th_o neces~tty . ~f raking together more profits to y1eld a fair dtVl·

dend. · 't f While it is certain, again, that the ~Jon Y ~

the men who give their adhesion to a gtven am~· aa.mation do so in the honest endeavour to amelio· ~ate their condition, it is also certain ~hat there are not a. few who gladly hail the oppor_turuty to clear out on terms which could not be obtamed save from a trust. Union with the strong may strengthen these weaklings, but the argument does not apply

APRIL 20, IgOO.]

both ways ; and anyway there remains the necesM sity of keeping up prices. In Germany, and especially in Americ~, there has been littl~ d.isM guise of the real motives of the trusts. It Is sig­nificant to find those who have upheld the idea of industrial combing,tion in the latter country utter­ing warnings on the subject of high prices. After the most remarkable rise ever known, especially of iron and steel, the new corporations are almost without exception doing what they can to maintain prices. The tariff keeps out the foreigner to a great extent; ~ut &latural laws. guard the publ~c ngainst extortion by monopolies, by making 1t certain that if the profits of any concerns appear too large, those profits will soon have to be divided with home competitors, directly or in­directly, and the later state of trade will then be worse than the earlier stat9.

Also, the temper of the public, in its self-govern­ing c~pacity toward such combinations under forms of law, is determined largely by what appears to be their conduct towards the public. It will not count for much in the end that they have raised the wages of those they employ. If there are 60,000 people who have some part in making tinM plates, there are over 50 millions in America who bear the cost of tin dishes. The companies are making up the record for themselves, and will in time be judged by it. "But," says the New York T1·ibune, '' this is a good time to remind them that the temptation to hold prices after a natural re­action from extraordinary advance has begun, is precisely that upon which nearly all import~nt monopolies have wrecked themselves. If they yield soon enough, competition is prevented and public favour is assured. If they hold a little too long, new competition is made certain, new com­panies are formed and works are started, and public feeling is so far set that later events m~y not change it." We have not gone to quite the same lengths as some of the American trusts which might be named. It is to be hoped we never shall ; because here, without free trade, the retribution is likely to come all the more swiftly and all the more relentlessly. •

THE MOTOR CAR EXHIBITION. A.t'i exhibition of motor cars, some of which have

been entered for the forthcoming 1000-mile trials of the .Automobile Club, was opened at the Agri­cultural Hall, Islington, on the 14th inst., and will olose to·morrow. The Exhibition contains a fair number of interesting exhibits ; but owing pos­sibly to the holiday season, many of those in charg~ of the stands proved to be mere appren­tices or the like, and far from competent to give us any technical information as to some of the most interesting carriages shown. The principal feature of the present Show is the number of light cars, intended to carry a couple of pas­sengers only, and fitted with engines of 2i to 4 horse-power. Most of these are intended to use petrol or gasoline, but a car of this class, in­tended to burn heavy oils, is shown by Messrs. Roots and V enables, of 100, Westminster Bridge­road, S.E. This car has a water-cooled engine of 3 indicated horse-power, and weighs 5 cwt. empty. The advantage of the heavier oils is their safety, cheapness, and the readiness with which they can be purchased at even the smallest villages. On the other band, they seem to cause rather more smell than the gasoline, and necessitate the heating of a vaporiser in starting. In the c~se of the car in question, this operation is said to take only 6 minutes. The oil and water tanks eAch hold enough for a run of 5 to 6 hours, and the makers state that the car has been run a distance of 60 miles without a. stop.

-E N G I N E E R I N G. the public is concerned, a. motor car may, owing to the powerful brakes with which it is provided, be run with safety at speeds much in excess of those now permitted to horse-drawn vehicles, but the public is slow to realise this, and any attempt to emulate on our roads the speeds attained in France would be very likely to result in the complete strangling of the industry. Whilst, as already stated, these racing vehicles are not in evidence at the Hall, tqe vi3itor has, nevertheless, an opportunity of studying recent French designs of less ambitious character. Panhard and Levassor carriages of different patterns are shown by the Motor Manufacturing Company, Limited, of 47, Holborn, E.C., whilst tricycles, q uadricles, and the like, of the De Dion type, are exhibited by many firms. A general review of the exhibits leads to the conclusion that water-jacketing is coming more and more into favour even for com­parative small engines, the air-cooled motor being almost confined to cars of the cycle pattern.

A particularly varied exhibit is that of the Auto­mobile Association, Limited, of Prince's-road, Holland Park-avenue, W., who show De Dion, Benz, and Mors cars using gasoline, a finely de­signed electrical carriage of American make, as well as K och cars, designed for using heavy oils. A good selection of motor car sundries is also on view. Another interesting exhibit is that of the Motor Carriage Supply Company, Limited, of 17, Balderton-street, W., who, in addition to a Cannstadt-Daimler sporting car, fitted with an engine of 6 horse-power, show one of the Simm's motor wheels fitted with motors of 2f horse-power, one of which has been entered for . the 1000-mile trials. An electromagnetic igniter of light weight and simple design is used for these motors. The standard pattern of the engine used is horizontal, and has very deep cooling flanges. The speed is regulated by alter­ing the point of ignition by a simple cam action, and it is stated that a range of from 200 to 2500 revo­lutions per minute is thereby attainable at will. The cars shown by the Motor Car Company, of 168, Shaftesbury-avenue, W.C., are peculiar in that the motors are all placed at the front of the cars, but drive the back wheels. One of these, fitted with a 3! horse-power water-cooled motor, has been entered for the 1000-mile trials.

But few electrical cars were on view, and appa­rently this type is going out of favour, probably owing to the delicacy of the batteries. The accu­mulator manufacturers are, it is true, quite pre­pared to maintain the batteries in working order at a reasonable rate, but their guarantee is always dependent on the condition that the voltage shall never be allowed to fall below, say, 1.8 volts. Ex­perience seems to show that the ordinary run of attendants cannot be relied upon to observe this condition ; and as a consequence the item of renewals becomes so expensive that, in spite of its cleanli­ness, absence of smell, and smoothness of running, the electric car has found comparatively few patrons.

In the heavy car department a fine exhibit is made by the Thornycroft St.eam Wagon Company, Limited, of Chiswick, who show a 3-ton steam wagon and 2-ton trailer constructed by them for Messrs. Harmsworth Brothers. A very inte­resting exhibit, but one concerning which we were able to obtain little technical information, is the light Brown-Whitney steam carriage, shown at the stand of Messrs. Brown Brothers, Limited, of Great Eastern-street, E. C. The steam is generated in a vertic~l steam boiler using petroleum as fuel, automatic arrangements being provided by which the fire is regulated by the consumption of steam. The engine hl\s two steam-jacketed cylinders, and drives the back axle by chain gearing.

THE PARIS INTERNATIONAL EXHIBITION.

(FROM OUR SPECIAL CORRESPONDENT.)

PARIS, April13, 1900.

The vast majority of the cars, however, make ~se of the lighter petroleum spirits, and great mgenuity has been exercised in the design of the.ir details. Owing to the benevolent manner in whtoh the authorities in France have regarded the motor c~r question, French manufacturers have had a considerable start of our own, and many of the best English-built cars are still made to French designs, with little or no modification. None of the very powerful racing cars which have been de­veloped across the Channel are, however, on view at th~ Agricultural Hall ; and, in fact, their use in this country, in the present temper of the J>Ublic, wo~ld be certain to lead to road regulatiOns so strmgent as to hamper perfectly legitimate traffic. Of course, it is quite true that so far as the risk to

THE almost miraculous changes which are effected upon the grounds, and within the buildings, of a great Exhibition, during the twenty-four hours that precede the official opening, can scarcely be imagined by those who have never witnessed the transformation. Roads that were almost impass­able to wheeled vehicles are converted into well­levelled and gravelled paths; the indescribable conf11sion of packing cases, scaffolding, and general debris, have given place to something like order, and even attractiveness, in the lawns and flower-

beds ; the army of miscellaneous sea vengers and labourers has made way for regiments of soldiers, of gendarmes, who not only preserve order, but contribute picturesqueness. Within the buildings the changes wrought in a few hours are scarcely less striking, for there chaos has yielded to phe power of a concentrated organisation, and a fac­titious air of completeness has been made for the moment to afford some suggestion of readiness. It is needless to say that all these smiling changes are but temporary, and on the morrow chaos comes

• agam. . As a matter of course, all these seeming miracles

will be worked during the following twenty-four hours ; but, unfortunately, the utmost that can be done must fail to satisfy even the least critical of the visitors who will crowd the Champs de Mars and its annexes on Sunday next. A hurried walk through the vast collection of building3 will prove only too plainly the soundness of this &ssertion.

It must be remembered, however, that it is a tradition that Exhibitions are always in arrear, and that is for the most pa}.'t the fault of exhibitors, who are always slow to install their show cases and their goods, and to whom the management has not the courage to forbid the completion of this work after the doors are open to the public. Still, on this occasion, the administration made itself specially responsible for completeness on the date of open­ing, by unusually strict regulations as to the limits of time for the reception of exhibits ; and as events have proved, if exhibitors had conformed to these regulations, their packing cases would, for the most part, have had no buildings to receive them. In the course of our inspection we shall see that there are a few exceptions to this general rule, but the impression conveyed by the existing state of things is that many weeks must pass before the public will pronounce that the display is complete.

THE MoNUMENTAL EN'l'RANCE.

ln collecting the materials for this hurried review, we naturally commence our promenade by the monumental entrance that offends the eye from the Place de la Concorde. A description of this curious and fantastic structure, especially as regards its ex­tremely skillful ironwork now embedded in the decorative plaster, has already appeared in ENGI­NEERING (see page 314 ante), and the unfavourable criticism we then expressed is justified by the out­spoken severity of Parisian opinion, which is loud in its ridicule of its form and glaring colour. Now that the entrance is completed, the work ap­pears even more unsatiefactory than could have been expected, especially since the statue in­tended to represent the Ville de Paris wel­coming her guests, has been put in place. This allegory is personified by a woman in very modem ball costume, and th~ effect produced is of a most disagreeable character. To make matters worse, the statue is of gigantic size in proportion to the entrance, at the summit of which it stands. As to the gate­way, its triangular form and the three supports upon which the arches stand, convey neither an idea of usefulness nor of stability. One would have thought that at least this triumphal entrance might have been finished on the opening day. The paint­ing, however, is incomplete ; the electric light wires have to be laid, a very large number of lamps to be put in place, and much paving and asphalting to be put down. We may remark in passing that the domed roof of this strange structure, although quaint, is certainly beautiful, but the statues which freely decorate the work near the level of the ground are far from satisfactory in their design and execution. For some strange reason the floor­ing beneath the dome is depresssed below the sur­rounding level, so that it will freely collect the rain; and as no means appear to have been provided for carrying off the water, considerable incon­venience to the public should result. Fortunately, it is not probable that there will be any great passage of visitors through this remote entrance during the early days of the Exhibition, because at least one-half of the turnstiles give access to ground which has not yet been levelled. We have already explained that, while the circular arrange­ment of turnstiles is ingenious andadmirablyadapted for dealing with a large number of people, these latter will find themselves, after passing through, in­conveniently crowded, especially on the side nearest the Seine; this inconvenience will be greatly in­creased, for some time at all events, by the bad condition-and even by the non-existence-of paths and roads for circulation. We may also note that

520

~'he gate of honour, which is placed at the bottom bf the monumental entrance for the special use of Sovereigns and other great personages, opens ex­actly opposite a row of trees which the Paris Muni­cipality would not allow to be disturbed ; this obstacle will certainly interfere with the conveni­ence and effect of State processions. On passing into the Exhibit ion grounds we come to some large areas laid out, and to be laid out, along the bank of the Seine; these will be reserved for horticultural exhibitions, and here the work may be considered to be well advanced, because the ground is ready and much planting can be done in a short time; for the moment the paths are badly cut up by the operations of the gardeners. F ollowing the route on the side of the river we reach the broad avenue, from which a view of the Alexander Ill. .Bridge and the Invalides is obtained. From here a good idea can be obtained of the general effect, and one can judge of the admirable proportions of the new bridge, which appears, however, to be somewhat overloaded with ornament, and especially with a great number of lamp-posts upon its balustrade. Before crossing the bridge ·to the Esplanade des Invalides we will glance at the exterior and interior of the two Art Palaces which stand opposite each other on each side of the n ew avenue, and will attempt to give some idea of their actual condition. (See the plans on pages 508 and 509 of this issue.)

THE FINE ART pALACES.

On entering the smaller palace the effect is absolutely charming; marbles of different colours have been employed in profusion, but with the most harmonious result, while the appearance of the interior court is even better than could have been supposed. So far as t he building is con­cerned it may be regarded as complete, although in many places the balustrades to t he staircases are absent, and probably two weeks will be required to put theRe in place ; meanwhile, the circulation of visitors will be dangerous and even impossible in places on this account. As for t he retrospective collections of French art, to which this b uilding will be devoted, they are at present entirely absent, excepting for those placed in one room, which is kept strictly closed. It is true there are a few statues in the lower galleries of the palace ; but, apparently, at least a month will pass before this building can be usefully visited by the public.

Passing now t o the larger palace (see page 281ante) on the other side of the avenue, it will be remarked that the curved and iron-covered roof, which rises above the classic stone colonnade, produces a worse effect than could have been imagined, the more so that the central dome is connected to the peristyle by steel arches that are utterly out of harmony with the stonework. The entrance stairways are com­pleted ; but the two slopes, giving access to the building, have been scarcely commenced, and cer­tainly two weeks' work will be required before these are complete. A part of the glazing still remains to be done. In the interior of the great hall the ground is still uncovered with the flooring, and work appears to be concentrated for the moment in t he erection of partitions, rising as high as t he first storey ; these partitions cut up t he extremely beautiful perspective of the hall in an unfortunate manner. It will be noticed now t he building is completed t hat the rounded ends have a form which is considerably out of harmony with the extremely graceful curves of the t russes carrying the parallel p ortion of the roof.

AB for the exhibits, t hey are waiting, piled up in packing cases, in the midst of debris and wagons employed for taking in, and .carrring out, material . The staircase of honour , w h1Ch Is at the bottom of the small transept at right angles to t he main hall, is nearly finished, although here also the balus­trades are not in place ; t he columns carrying th is staircase constructed of a mixture of iron and granite, do not appear satisfactory: If we add that the painters and decorators have still a great amount of work to do ; that there are as yet no signs of electric lamps (their absence suggesting that night­work is not carried on) which will be found neces­sary even in the daytime in som? parts of t~e building · that workmen are busily engaged 1n fixing th~ plaster decorations in the great oval hall of the small wing of the palace; and if we remark that there is nob a single installation ready for the exhibitors ; it will be realised that some weeks must pass before t he large Fine Art Palace ~il~ be complete. Outside, at the back of the build1ng,

E N G I N E E R I N G. electric wires are visible in all directions, being laid unprotected in the ground, which suggests danger even for temporary work during the six months' life of the Exhibition. In no place a.re electric lamps mounted on their brackets, and it is to be feared that no current will be available during the early days of the Exhibition, because, as we shall see presently, the power and electric installations on the Champ de MJJ.rs, are far from being com­plete.

THE CouRs LA REINE AND QuAI DE BILLY. Passing down the large avenue, we may give a

rapid glance of the buildings upon the right bank of the Seine. The principal of these will certainly be that known as " Le Vieux P aris,,, a very curious reproduction of the mediGeval city. Very con­spicuous also in the struct ure erected by the Ville de P aris and the Congress Hall ; both these are completely finished outside, but much remains to be done within. It may be mentioned here that in order to r each this part of the E xhibition from t he Champ Elysees, it is necessary to cross a public avenue, which intersects t he Exhibition ground, by means of an overhead bridge, in order to avoid re­payment for admission. This bridge is of timber, and is far from being complete. Under ordinary circumstances it would not seem possible that the bridge could be ready for traffic in less than four­teen days. On the opposite side of the river, two similar bridges are required, where the E xhibition grounds are cut by public avenues, and as these structures are no further advanced than that to which we are just referring, the inconvenience would be considerable if they were not ready by to­morrow.

THE E sPLANADE DES lNVALIDES. Retracing our steps, we cross over the Seine by

the Alexander Ill. Bridge, which, although not quite finished, is fully available for the circulation of visitors, and we reach the enclosure on the river bank leading to t he Esplanade des In valides. The faqades of the palace that fronts upon the great central JJ.venue leading to t he dome of the In­valides, appear much overloaded with orna­ment. I t is evident that in this part of the Ex­hibition a great deal remains to be done, possibly more than on the other side of the Seine, since the t wo buildings that face each other nearest the river are very far from being finished. Entering them, we are immediately struck by a very characteristic detail that illustrates the efforts made to hurry forward the work; large numbers of soldiers have been requisitioned to execute earthworks, and especially for cleaning and clearing away debris, so that the official cortege which will pass through the galleries may not find itself obstructed on its route. E xcept at periods of emergency like t he present, the advantage of employing military labour is more than doubtful, because, as the men are not paid, they have less inducement to work. Certainly, the unfortunate delay cannot, d uring the last few weeks, be placed to the account of the general Commis~ioner and his staff, who have lately practi­cally lived upon the Exhibition Grounds, that they might better urge the contractors forward ; t he successful completion of the task was, however, obviously impossible. Everywhere the same story has to be told ; as, for example, in the outer arcaded galleries, where the pain ters will still be busy for several days, as well as wit hin the build­ings, where the flooring is now being laid, and, of course, where no installations of exhibits can be completed. On the first storey, in t hat portion to be devoted to the decoration of buildings' exhibits, matters are somewhat more advanced, because the flooring was laid upon the galleries during an early stage of the work ; but t he staircases will scarcely be finished in less than a fortnight. Elsewhere, the exhibits are better advanced; but t he circulation of visitors on t his upper floor will scarcely be possible until the gallery handrailings are fixed. The remainder of the range of buildings on the left side of the E splanade des Invalides, is practically finished, and the show cases are in position ; here as well as in many other parts of the Exhibition, the delay appears to be the fault of exhibitors whose pack­ing cases to a large extent have not yet been re­ceived. P ossibly the slowness in delivering t he e cases may be partly due to the very primitive means employed in h(-1.ndling them; manual labour being the chief method, and as labour is scarce in Paris, the quality available for th is particular work is not such as to insure rapid execution. In t hese buildings, as indeed throughout the Exhibition,

[APRIL 20, I 900.

the ~ystems of water . mains, standpipes, and all app~ances for pr?tectlon against fire, appear to be admu:ably conceived, carrried out, and complete. Crossmg the c~ntral a venue of the Esplanade we enter the opposite r~nge of buildings, which are to a large extent occup1ed by foreign exhibitors · the fa~des of these buildings are still more highly ~eco~ated t~an those facing on the Seine, and gold Is. mixed WI~h th~ crude whiteness of the plaster, With more liberahty than good taste. Entenng first the .Belgian and Russian Courts, we find it im­possible to make any comparison in the interest and importance of their exhibits, because most of the~ !l're still in the~r packing cases, although some exh1b1tors have t.he1r goods coml?letely installed ; so far as can be Judged, t he Russian Court will be of remarkable beauty and costliness, and will con­ta..in objects of the highest interest. After having, w1th d1fficulty, surmounted the accumulations of Russian packing cases wait ing to be opened or re­moved, we reach the German Court where a sim.ilar condition of things prevails. The Un1ted States Court appears also likely to be fitted up regardless of expense; this court is no further advanced, though it may be a satisfac. tion to note that Spain is yet more backward ; Sweden, on the contrary, has managed to get its attractive and interesting exhibit almost into a state of completion. The space devoted to Great Britain, which is very well located near one of the principal staircases, presents a contrast of finished exhibits and vacant spaces ; that so many British exhibitors will be in readiness by the date of open­ing is due largely to the energy of Mr. Thomas Cope, of thd firm of Messrs. H enry J ohnson and Sons, who have the interests of many British exhibitors in their charge, as well as to the efforts of Mr. Arthur Day, who is also looking after a number of British exhibitors. In the Italian Court there is a great accumulat ion of decorative and other art marbles waiting to be raised upon their pedestals. The little Danish Court is attractive and well advanced ; that of Austria, on the con­trary, is sadly b~ckward.

On every side we notice that, two days before the opening of an E xhibition to which the public will be admitted during the evening, not a single elec­tric lamp has been hung. We need hardly stay to look at the various annexes which are parallel to, and at the back of, the principal buildings between the latter and the movable sidewalk and electric railway ; these annexes are not much further ad­vanced than the principal installations, and it is probable that they will be somewhat neglected by the public, because they lie outside the line of general circulation. Continuing our walk through the buildings towards the Seine, we pass through the extensive J apanese Court ; here will b~ ex­hibited a very large number of art and other obJects, if we may judge from the enormous number of barrels piled upon the floor, and which serve as packing-cases. Finally, the Swiss Court seems as if it will be ready in a few days, for although there is much unpacking to be done, all the show cases are ready to receive exhibits.

I t may be men tioned that the handling of all packing cases intended for t he Esplan~de. des In­valides is assisted by a small track runrung to a stage placed above the goods station of the In· valides, which at t his point is several metres below the surface. The packages are taken by a steam crane and placed on small trucks, which are then transpor ted along one or other of three ?ranches of this t rack to the central avenue. The bnes do not at any place enter the buildin.gs, .whi?h has .caused considerable delay and comphcatwn m mo~mg the goods; and many exhi?itors ~a.ve found It more convenien t to cart their packmg cases from the different Paris railway stations. Fro~. what we have said, it will be seen that the conditiOn of the buildings and their ?ontents on. the Esplanade d~ Invalides is very uregular; In many cases th';S part of the Exhibition may be r~ga.!ded .as pra~ht cally complete; in many others It lB eVIdent t a a Iona delay will be necessary to render them fit to recei;e the public.

THE STREET OF N .ATION8.

Passing from t he Esplanade des Invalides we come to the Street of Nations, a title borrowed horn the Exhibit~on of ~878, wh~~ a some;:a: similar range of mternatwnal pavilions form strikina feature on the Champ! de Mars: Close here is

0 a part of the moving sidewalk, ~htch w;@,

experimentally at all even ts, in workmg or er

,

APRIL 20, 1900.]

the day before the opening. I? is s.tated i~correctly that the two platforms of whiCh 1t conststs. could

t be operated because no current was available. T~e fact was that the syndicate w~s una:ble to ~et oun-ent from the Moulinaux electno statiOn, wh~ch the Western Railway Company w~s construct~g for its own local line, . the ~ermmus of whiCh · at the Invalides StatiOn. However, the plat­form was in motion, which showed that cu~e~t had been obtained from some source, and 1t 1s to be hoped that the same facility will be secured

romptly for the electric railway. In our last ~eek's article we gave .the lis~ of the pav~lions belonging to the respective natwns. There 1s no necessity therefore, to repeat it here, but only to say a fe~ words as to . their conditio~ at th~ ~ate hour of which we wr,Ite. The Itahan Bu1ldmg, finished outside, presen~s an appeara~ce of e~t.ra­ordinary confusion '!it~In. Th~ Turkish Pavihon is finished neither withm nor Without. The enor­mous building of th.e United States i~ ~ractically ready. 'At present 1ts contents are hm1ted to a typical post office, which will be put in practical working for the benefit of American visitors to the Exhibition. The Danish Pavilion 'seems complete but devoid of any con~nts. rr:he san;te ~emark applies to that of Austna. Thts palace IS very costly and elabor~te ; its c~ief internal feature is a monumental sta.rrcase leadmg to the first storey ; the whole of the elaborate decoration is in excel· lent taste. The little pavilion of Bosnia is a gem of Oriental architecture, about which we shall have more to say on a futu~e occa-sio~. It is almost entirely finished, and IS filled w1th ~xamples of native industries and n~tural colleclaons. The Portuguese Building, which is practically complete, will be almost wholly occupied with exhibits relat­ing to forestry and sport, but no order h~s yet been set upon these various objects. Peru has finishe.d its pavilion, and has even fixed most of the electric wiring a phase of progress which is rarely to be found i the interior of the building is filled with packina cases yet unopened, and the show cases are not installed ; in this connection it is interesting to note that a scarcity of glass has been a cause of delay in the' completion of the show cases. Owing to protection, glass is an expensive article in France ; at the same time it is cheaper to obtain it on the spot than to import it and pay duty ; on the other hand, the protection afforded to glass manufacturers has had the natural tendency of limiting the power of output, and consequently just now the supply is not equal to the demand. The Hungarian Pavilion has been completed for a considerable time, so far as regards the exterior, but of late no progress has been made with the internal arrangements, and the entrance is encum­bered with packing cases which have not yet been admitted. The same rema1·k applies to the Persian Building, the architectural features of which are excellent, although far from being of a national character. The British Pavilion, compared with those of Belgium and Hungary, is on a very small scale; it appears well advanced and will no doubt be completed in a short time. The Belgian Pa vi­lion will, when completed, be a copy of one of the most beautiful Hotels de Ville in the country so rich in medireval municipal architecture. Here the outside decoration remains to be completed, and it would be premature to talk of the definite installation of its contents; masses of show cases await the time when they can be put in place and filled. It should be remarked that all these pavi­lions are constructed on a half basement over the lo~·level railway of the Esplanade des Invalides ; thiS arrangement raises the buildings 6 ft. or 7 ft. above the ground level ; the staircases which will have to give access from this street of nations to the passages between the different buildings are for the most part absent, so that those which have not a flight of steps from the doorway, are practi­cally inaccessible ; some days at least must elap~e bef~r? these stairways can be completed. The Pavilion of Norway is practically finished, both as regards the structure and its contents, and the same favourable criticism applies to the Pavilions of Luxembourg and of Finland. On the other hand, that of Bulgaria is very backward. One wo~~ have expected to find the great German Pavilion ready ; much of the external decoration however, remains to be done and the installation~ of exhibitors are yet in mu~h confusion· a week however, will make a vast change in this 'building: Of ~h~ other pavili.ons, we may say that that of Spam lS f~t adyal)cmg towards completion ; aloes

E N G I N E E R I N G.

and cactus aro being planted in the gardens of the MonaQo Building; in Roumania, about half of the internal installation is finished ; Sweden has almost completed its somewhat rough and heavy pavilion, the contents of which are still to be arranged. The attractive Grecian Building is well advanced; and that of Servia is practically ready to receive the public. On the other side of the public avenue which interseots the Exhibition grounds, and which is crossed by a wooden bridge still unfinished, is the Mexican Building, nearly completed, but with­out any contents. On the whole, and making allowance for the delay which always attends the early days of an Exhibition, the Street of Nations may be said to be well advanced, and in a short time will ponstitute one of the most striking beauties of the Exhibition.

Continuing our walk along the terraced prome­nade on the bank of the Seine, we see the build­ings devoted to exhibits of heating appliances, of public charities, and of the Army and Navy; on the other side of the river is t he side-show of Old Paris which, as we have already said, is an ex­tremely interesting reproduction, without any tech­nical merit it is true, but possessing the great and exceptional distinction of having been completely ready for some months past, so that it will be able to open officially to the public on the inaugural day.

The Army and Navy Pavilion has passed through so many mishaps, the chief of which was the col­lapse of a considerable part of its framework, that it might reasonably be expected to be in a back­ward condition ; at one end it is not yet fully covered in, the contents, however, are being slowly installed. Behind this building are several annexes for the exhibition of war material ; one of the most interesting of these will be that of Messrs. Vickers, Sons, and Maxim; this pavilion, which is built to imitate a section of an ironclad, is complete, and the exhibits are for the most part installed. Un­fortunately, these annexes will probably be some­what neglected because they are located between the moving sidewalk and the electrical railway.

A short distance beyond is seen the great cupola which covers the pavilion erected by Messrs. Schneider and Co. for their own exhibits ; this building is in· a very backward condition, and will probably not be finished, and the exhibits installed, much before the end of June ; this delay is due partly to the strike troubles at Creusot last year, and partly to the great pressure of work which had to take precedence over their exhibit. In the pavilion of the Merchant Marine near by, the work of installation is being carried on with commend­able rapidity ; belonging to this is the annexe of the Peninsular and Oriental Company, somewhat overshadowed by the monumental model of a light­house constructed by Germany ; this is a reproduc­tion of the signal-tower at the mouth of the Wesel. Here we pause for a moment to throw a glance over the various pavilions scattered irregularly around the base of the Eiffel Tower ; as we stated last week, apart from a few pavilions erected by the smaller countries, a building to be devoted to French Government manufacture, and one or two club-houses, this part of the garden is filled with a variety of side shows.

THE CHAMP DE MARS.

We pass now into the Mines and Metallurgical Building, a description of which has already appeared in these columns. In the left-hand corner of this building the arrangement of exhibits is comparatively well advanced. There is still a good deal of flooring to lay down, but at least all the exhibitors appear to be on the spot, and are busy arranging their various stands. But when we pass to the right, matters are very different; every­thing is in the greatest confusion, in all directions excavations, in which will be built the foundations to carry the heavy metallurgical exhibits, are still in progress, and the whole of the flooring has yet to be laid. The upper galleries in this and the other buildings on the Champ de Mars are still unfinished, and the handrails are wanting as elsewhere; com­pletion will be impossible for some time. In that part of the building devoted to foreign exhibits, the condition is practically the same ; the Norwegian space is laden with packing cases ; in Belgiun1 some heavy machinery is erected, but the court is without flooring; the United States have enclosed their space with an elaborate colonnade, within which nothing but cases is visible. It may be mentioned here that in the absence of national sections, various coun-

tries have surrounded the limited. spac.es. placed. a~ their disposal in the different butldtngs w1tli enclosures more or less elaborate, in order that their exhibits might be kept distinct from th.ose, of adjacent countries. Whilst the metapurgical exhibit of Russia is almost completely Installed upon a relatively large area, those of Italy and Great Britain are only about half complete; the German space is covered with packing cases still unopened, and which are being shifted elowly by hand labour.

Much the same remarks apply to the adjoining building devoted to Textiles, the approaches to which are encumbered by loaded and unloaded wagons ; passing through the main transverse gallery which runs from t he Champ de Mars to the Avenue Rapp, and which remained for such a long time in an unfinished state, it is satisfactory to see that it is now complete but for the decora­tions. H ere a mixed crowd of soldiers and mis· cellaneous workmen are employed in sweeping and shifting the cases in a more or less perfunctory manner. Here also is a complete absence of electri~ lamps. From country to country the story is the same with the exception, perhaps, of the British Court, in which the installations are well advanced. It is not probably an exaggerated estimate that a month will still be required before this building and its contents will be ready for the public.

In the adjoining Machinery Hall (page 344 ante) where we come first through the French Section, we find matters in a much better state of completion than in the Textile Building ; naturally enough the pas­sages are still encumbered with cases, and the outside of the building with loaded a~d unloaded wagons. Passing into the transverse gallery which forms one of the wings of the Electricity Palace, and which is parallel to the boil~r-house adjoining the Avenue de la Bourdonnais, we find a state of things which does not promise well for an early supply of electric current. Scarcely any of the motors are completely erected, and a great amount of heavy machinery has yet to be put in place. In the centre of the building, that is to say, at the back of the Chateau d'Eau, and in the wing on the Avenue du Suffren side, which latter is reserved for foreign exhibits, the progress tows.rds completion is not better. On the upper galleries especially there is at present little but partitions, which will separate exhibits not yet arrived, or, at all events, not in­stalled. The staircases are employed as inclined planes for sliding up and down enormous cases, an operation which appears likely to cause them more or less damage. Here, as elsewhere, we notice the almost entire absence of cranes for handling the cases; very elementary mechanical appliances would save hand labour, much time, and some breakage. We hardly dare speak of the boiler-house on this side of the Champ de Mars, because in many cases the settings of the boilers are not complete, and much delay must arise before steam can be supplied ; that is to say, before electric energy for light or power will be available.

Entering the old Machinery Hall through one of its low side aisles, we notice that these are unfor­tunately much darkened by the boiler-houses, which adjoin them. In the interior of the gallery abso­lute confusion prevails; and it is certainly worthy of comn1ent that there is such striking evidence of delay in a building which already existed; no doubt exhibitors are largely to blame for this. It must be admitted, however, that a large part of the new structures erected within the old building are far from complete, and the ground is covered with debris of all kinds. The Salle des F etes, which it was promised should be ready for the inaugural ceremony on the 14th, is for the moment inacces­sible on account of the forest of scaffolding, which is now being taken down in all haste. Though so much remains to be done, we believe that here everything will be in superficial order at least for the opening. Platforms for the ceremonial are being erected, and to the uninitiated it appears im­possible that the place should be ready in time in spite of the extraordinary efforts which are b~ing made. It is certain that when fully completed the Salle des F eteEa will be an extremely well arranged and very beautiful building, and it is much to be regretted that it should of necessity be hurried so unduly, for it is to be feared that much of the de· coration may suffer in consequence. On each side of the Salle des F etes, the great area of the Machi­nery Hall is devoted to agriculture and food pro. duct exhibits, on one side France, and on the other

522

foreign countries. The former, perhaps, is some­what more advanced than the latter. In the upper galleries, however, there is at present nothing but packing cases and confusion. The delay is especially noticeable among the German and English exhibits.

Returning into the foreign section of the Elec­tricity Building, we find the progress made very unsatisfactory, and but few of the installations are complete, whilst here and there one sees founda­tions ready for machinery not yet arrived.

The adjoining Chemical Industries Building (page 344 a·nte) is, like most of t he others, in a state of confusion ; this, however, appears to be more apparent than real, and probably in less than two weeks a state of relative com­pletion will prevail. Looking from this main entrance to the Chateau d'Ea.u, it is pleasant to mark the enormous change that has taken place during the last two weeks. A large portion of the scaffolding of the great hemicycle has been taken down, which means that not only is that part of the structure completed, but that the very beau­tiful decoration is also finished. The lower basins are also nearly ready to receive the water . The mains are laid for the most part, and the devices for colouring the jets of water are fixed. Still, of course, much r emains to be done, and the energy concentrated upon this part of the works will have to be maintained for some time to come.

In the F oreign Section of the Civil Engineering and Transpor t Building, which adjoins that of the Chemical Industries, the exhibitors are, as in so many other places, responsible for the general con­fusion. It is worth noting, however, that a crane for unloading the wagons is employed in the British Court. In the French portion of th is building the railway companies and the Minister of Public \Vorks will have extremely interesting exhibits which are practically installed. The Liberal Sci­ence and Education Building presents for the moment a labyrinth of partitions, many of which bear promising inscriptions, but li ttle else is visible even in the French Section. A very short time, however, should suffice to get this building into comparatively good order.

THE T.B.OOADERO.

Leaving the Liberal Arts Building we pass across the end of the Champs de Mars gardens to the P on t d 'Iena, which has been widened for the approaching t raffic in a very ingenious manner, to which we shall refer on a future occasion and which is now entirely finished. Reaching the Trocadero Gardens, we find ourselves in the midst of the Colonial Ex­hibition, about which it is practically impossible to convey any clear idea ; it is satisfactory, however , to note that in two weeks from now everything should be about ready, and at the present time several of the numerous cafes have opened their doors to customers. I t is certain that this portion of the Exhibition will draw enormous crowds of visitors, n ot only on account of its general air of attractiveness, but because of the varied nat ure of the pavilions and their contents, collected from all parts of the world. I t is a subject for sincere re­gret that so much has had to be crowded in so rela­tively small a space.

To summarise our impressions derived from this long and somewhat fatiguing walk through the Exhibition, we find a repetit ion of old experiences, a state of unreadiness both as regards structures and exhibits, which it appears impossible to a'foid. Upon the whole, the P aris Exhibition of 1900 will, upon its opening day, be in a more backward state than many of its predecessors. With t he vast ex­perience at the disposal of t he Administration, this state of things should not exist so far as the build­ings are concerned. At t he same time, it must be borne in mind that the elaborate plans prepared by the Administration have been seriously inter­fered with in many ways : by labour troubles ; by the difficul ty of obtaining the enormous amount of ironwork required at the time promised by the con­tractors ; and by a plaster-of-~aris famine .. These causes in themselves are suffic1ent to expla1n why the buildings are not complet.l8. As for the ex­hibitors, the case is hopeless; they never have been, and t hey never will be, ready by the pr~­scribed time · and, as usual, most of the responsl­hility of thr~wing open an unfinished exhibition to the public rests with them.

APRIL 14. To the foregoing ar ticle we will add a few words,

not about the inaugural ceremony which has re­ceived due attention in the daily press, but upon the

E N G I N E E R I N G.

work done within the laHt twenty-four hours, the result of which has fully justified our forecast. The ceremony took place as arranged in the Salle des F etes, and, although, as we have indicated, the building was far from being completed, neverthe­less it was ready to receive the official cortege, and no superficial inspection could detect any great shortcomings. That so much should have been achieved in so short a t ime, is one of the nineteenth century miracles, which usually precede the open­ing of a great exhibition. B efore t he numerous audience, amongst which seats had been reser\"ed for a large number of workmen, the Minister of Commerce, and the President of the French Re­public, proceeded to declare the Exhibition officially open, to the unanimous applause of those as­sembled, and among whom were representatives of all the foreign P owers ; to them the chief of th E:\ French State addressed a few graceful words. Mr. Loubet, and his cortege, afterwards walked through a portion of the Exhibition , commencing with the Champ de Mars, where he took boat as far as the Alexander HI. Bridge.

N ow that the E xhibition is opened, and despite the fact that so much has been successfully accom­plished, we notice that the French journals wisely counsel the public not to visit the Exhibition for at least two weeks, an advice in which we heartily concur.

NOTES. CoTTON SPINNERs' TRUST IN JAPA!'l.

FROM the J a.pan W eekly Mail we learn that t he cotton spinners of Japan have completed arrangements for a trust on a scale which would do justice to an American combine. They in­clude in their organisation the spinners of Tokio, N agoya, Osaka, Okayama, and Kinshin. The promoters explain that t heir information as to the condition of foreign markets, whether for the purpose of buying the raw material or of selling the manufactured, is now obtained at second-hand and at much inconvenience to themselves, and in the general interest combination and co-operation has become advisable. The trust, in order to cover ex­penses, will levy t he equivalen t of 6k yen per bale, and daily telegrams will be received from London and N ew York. A general profit of 7 yen (14s. 3!d .) per bale will be included in the selling price fixed by the trust, such price being determined with regard to the prime cost of the raw material and the expense of manufacture, but a bounty of 2 yen (4s. 1d.) per bale will be granted on yarns for ex­port , money for that purpose being obtained by a corresponding deduction from the profits on yarns for domestic consumption.

BLACK PoTTERY. The dull black of antique terra cotta, in which

the Greeks excelled, has always appealed to t he refined taste, whilst gay bright colours enjoyed more general favour. '£he black was produced by mixing finely powdered carbon with t he clay. Of late, the clay has been impregnated with hydro­carbons, under the exclusion of air, of course. When this operation is not conducted very carefully, a crust of graphite will deposit on the outside of the object. In the industrial articles which are now manufactured, chiefly in Germany, this crust is rather advantageous, as it increases t he impermea­bility of the .clay. In objects of art, however, which mostly come from Denmark, it is undesir­able. Le Chatelier has recently observed that the black colouring is much d eeper and more uniform when the clay contains, or is mixed with, about 2 per cent. of il'on oxide. It need not be pure oxide: the ferruginous sands of Ram bervilliers, for in­stance, give excellent results, and a mixture with green sand answers well likewise. The iron oxide apparently facilitates the dissociation of the carbonic oxide and of the hydrocarbons, so t hat the decomposit ion takes place at a lower temperature. Le Chatelier experimented with acetylene, and he kept his objects in an atmosphere of that gas for about a quarter of an hour. His communication to the French Academy does not state the size of the objects with which he dealt. The temperature must rigorously be maintained between 450 and 480 deg. Cent. 'Vhen the temperature is too low, the impregnation is not sufficiently rapid ; when too high, an irregular coating of graphite forms on the outside of the clay. The objects are after­wards baked in crucibles, packed with powdered charcoal or coke. F or t he sandy clay of Ramber­villiers he found a temperat t.Ue of 1200 deg. Cent.

[APRIL 20, 1900.

most suitable for this baking ; the clay then assumed a hardness approaching that of porcelain. Acetylene has become a cheap and convenient sub­~tanc~,. an~ it is satisfactory to find a new field for 1ts utihsat10n.

COAST D.eFENCE. . ?-'he ·' Var Offic.e _have come to a.n important de·

c1s1on 1n determmmg to purchase 50 acres of ground on the sh~res of t~e F irth of Clyde at a cost of 30, OOOl. \Vlth the v1ew of constructing a fort with mo~ern guns and barracks for 1000 men, for thia act1on reflects the view entertained at Pall Mall as to the general strategical advantage of immobile coast defence, as promised in the Queen's Speech in J anuary. There are many able strateaists who hold the view very strongly that safety depends solely on an invulnerable sea power ; but others are of opinion that some concession should be made in view of the possible occurrence of such panics as were created in the Atlantic freeboard States dur­ing the Spanish-American War owing to Cervera's '' fleet in being." If the coast-defence scheme sug­gested by this first instalment is thus intended, no one need object, as the fort may incidentally be useful in stopping such a foraying expedition, by a torpedo or gunboat, as greatly excited the good folks on the Clyde on a bright unday morning during the manmuvres some years ago, the lieu­tenant in charge carrying out his scheme of humili­ating the Clyde towns with realistic effects. But it would be idle to assume that because of this fort there should be the slightest relaxation in the direc­tion of insuring our sea. power. The expenditure on the fort, t oo, can be excused on the grounds that the Clyde, although it can never be a base, may prove useful in connection with the repair of our naval ships in time of war. .Again, it is our greatest shipbuilding centre; just now eight armoured ships, besides smaller craft, are being constructed, and the prospect of destroying ships in process of completion or of repair, would tempt the enemies' small craft into the inner waters of the estuary. The point fixed upon for the fort is near where the river widens into the estuary, a. little further down than the anchorage opposite Greenock. Tactically a site nearer the sea might have been preferable; but the existing submarine mines are close by the new site, and, moreover, the islands across tho Firth form three channels, any one of which might be taken by a small invading ship. The range of t he guns to be installed will cover the whole area of the inner part of the estuary to which all three channels give access. •

F RENCH CruTICISY OF BRITISH ARTILLERY.

We have long been accustomed to the excited ebullition of the Anglophobe French Press, and tho total disregard of facts which accompanies it. I t has done nobody any harm and goes unheed~d ; but when we find the scientific papers offerm.g misleading statemen ts, some remonstran~ lB

desirable, especially when the effect 18 to disparage British industry. La Nature- a journal of high scient ific repute.- has. pub· lished an article on English artillery m ~h.e Transvaal which is more remarkable for the or1g1-nality of' its facts than for its accuracy. The quick-fire guns of the Boers are lauded most uo­stintedly ; t hey are of French make .: and we are told that the Boers have no machme guns or mitraillouse as the French call them. It is added, "The succe~s which the Boers have obtained siJ;lce the opening of hostilities encourages theh ~o~clN100

that t hey have not had cause to regret t 18. ow, if one thing i.q certain about the Boer succ~~' and the occasional demoralisation of the Br1t1Bh attacking force it is that they have often been caused

' h "P P m" by the Maxim one-pounder g~-:-t e om· o , as it has been called. All military attaches ~~ve spoken most favourably of t~e great mobil1t~, rapidity of fire, and the destructwn wro~ght by thJ! weapon firing, at the rate of 300 p~r mm~te, she It which break up into seven or e1gh.t p1eces. a was probably conYenient for the wnter to foroet the presence of this weapon in the .Tra~vaal War, because he occupies the whole of h1s artiCle depre­cating it. There is no need to ~raverse the s~t~t ments made ; the British Admtralty adopte h because of its demonstrated euccess ; so th.at t. 0

" extreme delicacy " spoken of by the ~rlter 10

connection with the French Naval Maxim ~uns, into which various improvements ha!e been mt~­duced, must be due to these French unpro~emen · The Maxim of rifle calibre has been ~n t~verr, recent campaign, and "its t41~ to the ea en

APRIL20, 1900.] ENGINIEERING! . -~~============·=·==~==================~==========~~~~ ~ has had a . wonderfully convincing effect. It may b.e that the French will, as saggest ed, relegate it. to a secondary p osition; that is their affair. Again, as ,to the ebullition ~nd _evaporat ion of the water in the barrel-coolmg Jacket , . due t o long-continued fire, the Boars seldom fire 20, and oftener only four to six shots at a time, because intermittent .fire is more d emoralising, and as Sir Howard Vincent pointed out in his recent address at the Royal U nited Service Institution, the Boars show far more r estraint than our men. The only ebullition and vaporising seems to have been in the writer's mind. As a matter of fa9t , too, the French guns, like our big weapons, revealed their posit ion in firing far more than the Maxims, and as t o the relat ive advantages of the guns of various sizes, about which much is made, it need only be said that the success of the Maxim, both on the British and the B oar side, has justified its use. The requirements of an a_rmy are v~ried, so are the wea­pons. The editor of La Nat1.we, ho wever, may pos­sibly justify his vie ws on the plea that the produc­tion in his journal, with all its misrepresentations, has been quot ed in full by the Scienti fic Ame·rica11 Supplement, which ought to have known better.

•

THE JOHNSON-LUNDELL SYSTEM OF ELECTRIC TRACTION.

A NEW system of electric traction, or rather a system present ing new features in nearly every de­partment, is about to be int roduced into this country. It is called by the names of the joint inventors, Mr. E. H. Johnson and Mr. R. Lundell. The former is exceedingly well known here, as he has paid many visits since he came a.s Mr. Edison's representative in 1882, and greatly contributed to the success of t he Exhibit ion held at t he Crystal Palace; while the name of the latter has been rendered popular by the motors which he invented, and which are in use in many works 'and manufactorie3. These two gentlemen are the patentees of improvements in dynamos, motors, controlling switches, methods of motor control, and a surface contact syst em, which, taken conjointly, form an electric traction system having many points of interest at a time when munidpalities and private companies are contemplating spending many millions sterling upon improved means of street locomotion.

The salient feature in the J ohnson-Lundell dynamo is the form of the pole-pieces. These have been designed in such a way as t o render the machine ~parkless at all loads, and we have the assurance of Mr. H. F. Parshall t hat this condition is ful­filled, not only in a degree unattained by any other dynamo, but absolutely, there being " darkness " between the brushes and the commutator. In relation to this point the late Dr. John Hopkinson wrote : "The improvement is perfectly simple. The magnet is to be divided into two parts of about equal section, wound with the same coils of wire for exciting. One of these parts has a large polar extension so that the area. of armature opposed to it is considerable. The other has a smaller polar extension. The result is tha._t a comparativ?lY small current will fully mag­n~ttse the part w1t~ the large polar extens ion, but will n~t fully ma:gnetts~ the part with the smaller polar extens10n. On mcreasrng the current the part with the larger polar extension has its magnetism increased to a moderd.te extent only, while the part with the smaller polar. extension has its magnet ism much 11:1ore largely mcreased; the result is that the distor­tton of the field is effectively diminished, and can be so ~rranged that the point of commutation is not mater1a:ll~ altered. ~' It will be readily understood that th1~ IS a ~ost lf!1P?rtant matter in tram way gene­rator~, _m wh~ch shtftrng of the brushes to suit the load IS tmposstble, and that it involves no addition to th? cost. Indeed, as compared with the device of usmg an exce~di_ngly strong field, there is a great econo!lly;. and 1t Is ass~rted that these generators can be built wtth 20 per cent. less material, and at 15 per cen~. less co_st than corresponding machines of the ordmary des1gn. The curve of magnetisation pro­duced by the pole-piece is t he reverse of the curve of dema~etisation produced by the armature, and the result 1s a constant field. ~he motors are ca pable of having their field exoi tation

;~ned through a very wide ra nge, and thus the regula-IOn o! the speed of a car can be effected by uuiform sm~llmcrements and decrements wit·hout the use of re~stances. At starting a powerful torque is obtained :.n ~o energy is uselessly wasted, and as the excita~ ton ~~ r:duced by cutting out the field coils, the ~p~ Is Increased without shock to the passengers eao .;novemen_t _of the lever from notch to notch giving a um orm addttiOn ?f tw~ miles per hour. The two :otors can be used m senes or parallel, in t he usual

ay, and the~ can be reversed to act as brakes sending o;rrent back mto the line. This is not mereiy in case ~ e~e[1gency, but as a matter of general routine · spe01a Y on down-grades, where such an arrange:

ment is a material economy. By suitable excitation the motor, when reversed, will yield a current e-t a higher pressure than the line pressure, from its maxi­mum speed down to one-third that speed, and t his current can be sent back into the line, the descending cars aiding the descending ones, as if they were mechanically connected.

Surface contact systems have been before the public for many years, but they have made very little pro­gress. They are exactly what the municipalities long for, but none in this count ry, or in America, we believe, has had the courage to instal one. The multiplicit y of switches, and the danger of lea ving a contact " alive " after the car has passed over and ceg,sed to cover it, are·dangers which have hitherto frightened engineers. It is atated that 40,000l. has been spent over the J ohnson-Lundell eystem in experiments to eliminate all possible dangers, and that a short J ength of it has operated in N ew York for a year under all the difficult conditions which the climate of that city can furnish in such variety and abundance. It is claimed, there­fore, that there is no longe~· reason to doubt its safety or reliability. The surface contacts are, of course, " dead " a t all times, except when the oar is above t hem. To prevent them from being kept alive by leakage currents the switches are worked by a magnet carried on the car. This magnet, however, does not operate the main switch, but a light relay lever, which closes a circuit in which there is a reduced pres­sure of only 50 volts, to avoid serious sparking. The magnet ic circuit includes t he axles and wheels of the car, the rails and the tie bars between them, and hence, as the car moves along, it breaks the magnetic circuit most effectually, a nd the relay lever cannot be held over by residual attraction. The surface sy stem is more sightly than the overhead trolley, and less expensive and inconvenient than the conduit system, and it only needs its reliability to be demonstrated to secure its adoption.

To secure a further economy, it is proposed not to equip the down-grades with contacts. The car would run on them by gravity ; but, t o insure its cer tain starting, and also to carry it over short level lengths, it would be equipped with a small storage battery. This battery would be charged on the up - grades, and would be always ready for work. It is even proposed that extensions into distant suburbs should be worked by t he battery alone to avoid the cost of feeders, and this would be feasible, no doubt . But it is jus t in the suburbs that high speed is most desirable~ and this cannot be obtained by a bs.ttery, and part10ularly a small one. One of the chief merits of direct electric traction is that any amount of power up to 50 or 60 horse-power can be obtained when required, whereas with a battery one is restricted to 5 or 6 hon:;e-power. We hopo to see the Board of Trade restrictions as to speed relaxed some day, a nd should be sorry to find that the increased liberty so oBtained could not be rendered available. I.t would be a pity to handicap a promising system hke the Johnson-Lundell by rendering it dependent on accumulators.

THE WAR IN SOUTH AFRICA. To THE EDITOR OF ENGINEERING.

Srn,-The interest of the public for the past week has been fOC!JSSed on ColonelJ?algetty and the gallant band of colomal troops under his command, which has suc­cessfully beaten off a -. much larger force of Boars near Wepener, close to the Basuto boundary. The Boars appear to have attacked with unusual determination for two day8, a_nd to have suffered considerably, especially from our artillery (seven guns). Our men were practically surround,ed, so ~e cannot expect to hear the details of the fightmg unttl the Boars clear off, an operation which by latest accounts,_ they are now performing. If Generai Brabant be at Ahwal North, as stated, h.e was 70 miles south of the conflict, whereas General Chermside who is ~ow stated t? have occupied Reddersberg with ~ounted mfantry. artillery, and foot, woultl be about 50 miles west of Wepener. · ·

The main object of the recent audacious operations by the Boars must have been to prevent the collapse of de­fence by the Free Stater8, and to inapirit the whole of t~e commandoes by a few brilliant and daring actions w1th some of our small and isolated forces. It cannot be denied that they have been successful on the whole having dealt two very stinging blows on small bodies of our regular forces, tlie one ab K oom Spruit, the other near tJo Reddersberg, but our colonial troops at Wepener have turned the tables upon them, and thus caused a delay which may have important results if a suitable force from Bloemfontein be employed on their line of retreat. In any case it was a mere raid a flash in the pan, b~b it ha-s been· brilliantly executed and has suc­ceeded m a manner that could scarcely have been 1,\.ntioi­pated, and caul~ scarcely have occurred if our scouting had been effect1ve to the eastward of Bloemfontein. The success of this Boer raid must therefore be attri­b~te_d to our deficiency in horses, and the delay in ob­tammg remounts. <;">ur War Office is now very flush of ~oney, and,~be offimals should spend without stint at the stgn of the Nag's Head." As for horses to be found in that portion of tlie Free State under our command, they should be commandeered for the use of the Army whether their owners be willing or not. '

An immense am0untJ of organisation work must now-.: be going on at the seaport bases, and at the three ad­vanced bases-Bloemfontein, Kimberley, and Ladysm~th. · We also hear that Bloemfontein is being placed in a · sta;te of defence by entrenchments, therebY. making this advanced base more secure, and also enabling a smaller ·. force to hold it when the arm:y advances beyond it.

All these things require t1me, and "the man in the street, " who ,up to the present has been very reasonable, and often sagacious in his remarks and ideas, must exer­cise patience·:· During the interval the energetic corre­spondents of our papers will keep things lively by stating opinions when there is a paucity of facts. More­overi whe~ letters from specially paid correspandents are aoking, even the best of papera will not hesitate to publish letters from civilians and busybodies, who con­sider themselves fully capable to judge and decide upon all matters concerning tl:ie war, and especially the direc­tion thereof by our generals thousands of miles away. Thus, in J anuarr the TVmes published lettera from a dis­tinguished oivihan, who did no~ hesitate to blame ,Sir Red vera Buller for not attacking in force directly he · found that the Boera were attacking Ladysmith on January 6, forgetting apparently that certain prepara­tions are essential prior to an attack; that orders have to be drawn up and issued, troops collected and moved, and many other things done, all of which re­quire t ilfae. In short, General Buller was blamed for not doing the impossible. A letter from the same writer is now published in the Tinnes advocating the recall of a certain distinguished general. He may he right or wrong, but it certainly is wrong for the Times to publish such a letter, an attack on an officer with his face to the foe at the front, and who cannot, therefore, defend him­self. The trial of generals in the daily papers at such a time neither accords with British ideas of fair ~;>lay, nor assists to support that freedom of the press which is, or should be, founded on fair comment.

The rearrangement of commands in South Africa was published yesterday, and should satisfy those who recom­mend young officers as commanders. Of the 31 brigades only five are commanded by major-generals; 25 are com­manded by colonels, and one by a lieut.-colonel. A lieut.­~ener~l is in command <?f each division, except the lOth, m whiCh the command IS vacant; and the mounted in­fantry (now organised as a division) commanded by Colonel Hamilton, C.B. Major-General Sir Herbert Chermside, temporarily in command of the 3rd Division now at Reddersberg, is not mentioned on the list.

In N a. tal a little gunnery .practice a~d some skirmishing has occurred, one result bemg that Str Redvers Buller is the better able to locate the enemy's position.· The presence of our Natal army to the north of Ladysmith holds a strong force of Boars in its vicinity, and a waiting game here is our cue until the main advance occurs under Lord Roberts.

April15, 1900. Yours faithfully,

FIELD OF:~<--rcEn IN '84.

PERSONAL.-Mr. George Emest Nye, of the firm of Bra.dshaw, Brown, and Co., riverside specialists has been appointed (in conjunction with Messrs. Willian: Clarkaon and John 13ussey, of Poplar), _by the o~erseers, to value the factory and . other hered1taments m the parish of Poplar, for the purpos~s of. tJ~e quinquennial assessment, 1900.-The Blyth Sh1pbutldmg Company, Limited, of Blyth, Northumberland, announces that having taken over the docks and premises of the Blyth Dry Docks C01;npa~y, Limited, they have now five docks, one of whiCh IS 480 ft. long by 61 fb. wide, and is fitted with 50-ton sheer legs. The telegr&phio address of the company will in future be "Drydocks,, Blyth.

• . PROGRESS 0 1!' RAILWAYS IN JAPAN.-From a, recent 1ssue. of the Japan Times we take the following Table show~ng the d~vel?pment of railways in Japan since the~ first mtroduot10n m 1872 :

• -cc:~ .... - _ ..

0 • -o .... 0 Ill 0' OQ) 0~ .... a..c:~ ,..o .. bO Q) ~ ~..£::1

Fisoal Year. bOlD <IS Q)o Q) 8 . Q)C CISQ) .. ,o .... .og(ll ,o Q)• ,o~· o..cQ) 8~ 8 111 111 s·a> f!

• ....... ·- s:lc So~ =='~:; ·-Ho =='.., iH:P =='a.. eO ;:a . zcn z~o zr:. o •

1872-3 • • • • 18.00 6 10 68 75 . 1873·4 • • •• 18.00 6 10 58 76 1874-5 •• • • 38.27 12 22 144 167 187ft -6 • • • • 3'8.27 13 32 1-16 203 1876 7 •• • • 65.11 13 34 166 2i56 1877-8 . • • •• 65.11 19 38 160 820 ' 1878 9 • • • • 66.11 19 38 166 363 1879-80 • • • • 73.22 23 38 173 • 413 1880·1 • • • • 78.25 26 36 178 446 1 1881-2 • • • • 122.26 88 45 203 627 1882 3 • • • • 170.26 40 47 240 503 1883 4 • • • • 244.64 63 65 346 727 1884-5 • • • • 262.37 62 68 373 801 1885 6" • • • • 358.41 79 66 890 922 1886-7 •• • • 480.64 92 72 485 1,003 1887-8 • • • • 539·67 114 83 451 1,251 1888 9 • • • • 902.19 174 :28 669 1,732 1889-90 • • • • 1236.34 225 176 887 2,662 1890-1 •• • • 1399.14 290 264 1217 3,387 1891-2 • • •• 1716.lt 347 293 13<.2 4,180 1892·8 • • • • 1870.77 365 318 1369 4,672 . 1893 4 •• • • 1938.52 394 863 1453 5,816 1894-5 • • • • 211R.24 467 440 1646 6,413 1895·6 •• • • 2290.43 528 522 1943 7 ,391' 1896-7 •• •• 2507.11 538 612 2271 8,900 1897-8 • • • 2948.()7 746 89! 2900 10,471 1898-9 •• • • 8410.50 802 1103 3811 14,134

Th~se _figures do nob include the railway in Formosa, wh1ch 18 now par.t of the Japan·~se ~mpire; but, as yet, the amount of rallway constructiOn 1n that island has not been great.

E N G I N E E RI N G.

COAL-HANDLING PLANT AT THE WANDS- rail level. The grab is of ! -ton capacity, and the WORTH ELECTRIC LIGHTING STATION. crane will carry this load without difficulty a.t its ex­

treme working radius. The motors used are of the THE steady growth in the size of electric lighting W estinghouse type. All motions of the crane, including

stations, with the consequent necessity for the handling tra,relling, luffing the jib, hoist ing the crab, and swing­of enormous quantities of fuel, presented to engineers ing t he load, are effected by power, friction clutches a new problem, the different solutions of which are of being employed for throw ing the mot ions in and out much interest. The plan now generally adopted, of gear, and for reversing. The crane delivers its load which is a distinct innovation in boiler-room practice, on to the hopper of a large weighing machine, shown is to place the coal store above t he boilers. The latter in Figs. 8 and 9, and which has a capacity of 40 tons are Yery commonly provided with automatic stokers, per hour. The hopper of this machine is constructed and the coal for the fires is simply shovelled into of ! -in. plate, and will hold about 50 cubic feet of coal. shoots, leading direct from the floor of the coal store A hopper of somewhat smaller capacity is placed below above to the hoppers of the mechanical stokers afore- the weighing ma.chin~, and directs the coal into one said. This arrangement greatly reduces the labour of of Graham's automatic feeders, driven by a chain and the boiler-room attendants; but it will be seen that it sprocket-wheels from the bottom shaft of the main involves the raising of the whole of t he fuel used to a elevator. The rela.th·e position of the weighing considerable height above ground-level, and its dis tri- machine and this elevator is clearly shown in Fig. 8. bution there to the bunkers, which in some cases hold This feeder delivers the coal into the elevator boot in the aggregate betweon 1000 and 2000 tons. Various in definite charges, and all danger of choking t he plans have been adopted by different engineers for elevator is thus avoided, and the load in the buckets accomplishing this work; and we illustrate on the of the latter is equalised. As Phown in Fig. 8, this present page and page 516 the plant chosen by Mr. A. elevator is 47 ft. long between shaft centres, and is J. Lawson, of Artillery Mansions, S. W., when design- . supported at its upper end on a steel tower some •

•

•

•

•

•

.

Fig.1.

·~;)] A;/

• • I

t I

• I

'6 • -. "" (~ I I

• I

• •

FrfJ.Z.

)

- . (")

I t I I I t

-- --- ----~: s'-· - -- --·- -- --- --I t

I I ' ~ --+4: :J - - -- -1

I

•

•

Levw I • Gro

Fi!J .8. 2 ".2:

, .. 6a-s TulJe

- -- --------------------------

•

. 3Ji;. - - ---------- --

I ______ __ J __ _

~ I

~ . --7: 31;,.. ---~-J~ - - -- - ---· - -;- - -- - i

• M 10 I

• . I • I

t'

--------------------- -- -

ing the Wandsworth station of the County of London 40ft. high, constructed out of 8 in. by 5 in. rolled­and Bru3h Provincial E lectric Lighting Company. steel joists, having feet, a.s shown in Fig. 10. This plant has been executed by Messrs. Graham, A back view of this tower, showing in position Morton, and Co., Limited, of the Black Bull-street the 5 horse-power electric motor operating the Works, Leeds, a. firm which previously bad consid er- elevator, is represented in Fig. 7. The buckets able experience in w ork of a. very similar character are 24 in. w ide. The elevator casing is of iron plat­for gas plants. _ . . . ing No. 7 B. W .G. thick, st iffened by 3 in. by 3 in.

The W andsworth stat10n , as descnbed 1n our 1ssue by ! in. angles riveted to the sides and front. Green­of February 16 last, is situated on the River W andle, hear t liners supported on angle-irons run the whole nea r its confluence with t he Thames, and the coal used leno-th of t he casing, and serve as guides to the is conveyed by ba rge t o a. wharf belonging to t he sk idder bars, thus subs tantially reducing the noise works. An electric locomotive crane, running on ra ils whilst t he elevator is at work. This elevator de­of standard gauge laid on t he wharf, is used t o lift the livers t he coal on to a 20-in. push-plate conveyor coal out of t he barges, and to deposit it in a. hopper of supported on a lattice girder , as shown in Fig. 1. A a weighing machine, whence it ~asses .t? t~e b~ot of cross-section through this girder is illustrated in a. 24-in. inclined elevator, shown 1n pos1tlon 1n Ftg. 1. F ig. 2, whilst Fig. 3 is a portion of a side elevation of This elevator passes on the coal t o a long push-plate it t o an enlarged scale. As shown in Fig. 2, t he con­conveyor, supported on lattice girders, and which veyor is covered over with corrugated iron, No. 20 delivers t he coal into the hopper or one or other of B. W .G. thick , so as to p rotect the fuel from the two smaller elevators, which raise the coal another weather in its progress to t he store, whilst a footway 16 ft . or so, and pass i t on to one of t wo push- provided a longside gives ready access to any par t icular plate conveyors, running t he whole length of_ th~ coal point. This conveyor is of the push-plate t ype, and store on either side of it . 'l'hese conveyors d1stnbute is 179 ft. long between the centres of end shaft s. t he c~al to the bunkers, where it is k ept till needed A t the station end, two t raps are ar ranged, leading in t he boilers. respectively to the hopper s of t h.e bunker conveyors

The electric crane referred to has a j ib with a over- already referred t o. The relattve arr~ngement ?f bang of 30 ft. , and will lift to a height of 20 ft. above . t hese hoppers and the long conveyor 1s shown tn

[APRIL 20, I 900 . •

Figs. 4 to 6; which also show the driving gear an ele?tromoto~ being used as in t he case of the elev~tor. T~ts. motor 1s of 20 ~orae-power, and in addition to dnvmg the. long 20-m. conveyor, also drives the ele­vators leadmg to t he conYeyors distributing the coal to the coal bunkers. These latter conveyors are also of the push-plate type, and are each driven by a. 7i brake horse-power motor. They measure 73ft. between centres of end shafts, and are 20 in. wide. Each of these conveyors has eight traps, which can be opened or closed at will, corresponding to the different bunkers

_The bunk.ers are b~ilt u~ of i -in. plate, stiffened by 3 1n. by 3 10. by f m . T s. At the front each is provided _with a. sliding door, on lifting which the coal ~una out m to a cent ral gangway, ~n~ is there loaded mto the hopper of a. portable we1ghmg machine run­ning on narrow-gau~e rails. An automatic device records the number of times the hopper of this machine is filled, and this constit utes a check on the a.coure.cy of th~ b~nker man. The weigh~ng accomplished, the macbme 1s run over a. shoot lea.dmg to the mechanical stokers in t he boiler room below, down which the charge of fuel is emptied. It will thus be seen that all coal entering the works is weighed twice; once when loaded out of the barges, and, secondly, before being passed into t he fires. The two weighings check each other, and also render it ea.sy to figure the amount in store at any date. The designed capacity of the plant is about 40 tons of coal per hour, conveyed from barge to bunker. .

NOTES FROM THE UNITED STATES. PHILADELPHIA, April5.

LARGE consumers of iron and steel are anxiously awaiting developments that will point to a downward tendency. A good dea.l of bard work has been done by interested parties in bringing about a. depression in prices, and they have managed t he business with credit, but without success. The developing require­ments of the country from week to week seem to forbid any pronounced decline. Consumptive capacity is very large a.nd would be larger with lower prices. We have two t hings to depend upon, namely, increa-sing domestic demand and awaiting foreign demand. Should prices recede a litt le, t here is no doubt whatever but that a large amount of withheld business would appear on the market simultaneously, with a sufficient de­cline if foreign demand would spring up, par ticularly in crude iron. Our large exporting houses have turned d own large quantities wit hin a week. The only weak­ness wor t h speaking of is in forge and foundry irons. Bessemer pig is high, and production is barely ade­quate. Transportation charges for ~re and coal, ~ well as all iron products, have ~een mcreased. T.hts week the higher wages rate goes m to effect, a.m1>unt1~g to 20 per cent. Thes~ ~ded elements of ~ost forb1d any material change m 1ron or steel quotatiOns. The managers of the numerous big enterprises are ~ecog­nising this fact, and it is probable t hat they w1ll be heard from in a very short time, with orders. of s~ch magnitude for all manner of equipment as w1ll bnng prices up to where they have receded. The orders this week for plate iron and steel convince the most sceptical that those who expected cheaper plate know the opportunity has passed. In merchant steel there is a stronger inquiry. Aprilll.

Peculiar conditions are gathering around the iron trade. Those concerns which have their own ore mines and transportation fa.cili ties a.re able to make iron and steel products considerably below .th?se who have to supply their own raw ma.~na~a. Thts 18 where the hitch is coming. Crude mater1al1S several dollars higher than a year ago, and finished produc~s. are some dollars lower than a. year ago. The compe~1t10n of ~he concerns which have t heir own ore and p_•g-Iron ma.kmg facilities is beginning to cut hard a.g~mst t~ose who have not and some of t hese concerns wtll be, m course of time, ~nd probably not a very long time, crow;ed ~ the wall or compelled t o sell out. In other wor s! ~ e

. . · t ' ll t' · g CompetitiOn centrahsmg process ts s 1 con mum · f in finished materis.l is stronger t han. ever, an~ ther~ ore prices are pointing downward, part1cularly m bar rro~. The announcement is made to-day that the Carne~1e Company has set aside 1,000,000 dols. for the erectiOn of two very large merchant bar miliA. Th.i.s m~n~ ~ competition wit h the public iron compa.mes; bl a/ r means cheaper iron and a good deal more trou. e o

th There 1s con-bar manufacturers wherever ey are. . d siderable activity in plate and structur.a.l ma.~rl&l, ~as pr ices are firmly maintained.. Very h ttle c . an~~r er occurred in prices for scrap tron, but t.he~6. 18 a. pic:ed suppl v now coming in sight, and stoc 18 emg · · g

, . · d It · rather surprlSlD up wherever 1t can be toun · 18 . r ei bt t hat so much scrap can be found after SI~ U daYs months of apparent scarcity: No.~ ftun~~l:t~ 35 dol~~ tank-plates 2 cents, steel ratls 35 o ;·b l. in sight to 36 dols. There is a la~ge v~lu~e 0 us~f::sdema.nd. from all quar ters. Macht~ery ~s m_ very ascouth is creat· The springing u~ of texttle mdtllfs m tth~ile machinery, ing an extraordinary deman or ex and all makers are oversold.

-·

•

APRtL 20, I 900. J rrHE ]1;NGINE OF THE COR\TETTE

' ·GENERAL BAQUEDANO."* By Mr. ~L~GNUS SAKl>I_ ON, Member.

THE corvette General Baquedano is a training or school ship of 2500 tons displacement. She was built by Sir w. G. Armstrong, Whitworth, and Co, Limit~d, to the order of the CbiJian Government, and her machmery was constructed by Messrs. Ha\vthorn, L eslie, and Co., Limited. It was desirable that this vessel shollld ~e able to steam very economioa.lly at low speeds, and 1t was decided to a.dop_tl a eix-~ylinder engine, which I had 8uygestrd some t1me prev10u~ly.

The steam trials of the vessel have recently been com­leted, and I am enabled, t~rough the cour~~ of R ear­

~dmira.l CastilJo, the P resident of th~ 9hihan Naval Commissi0n in Europe, and by the permtsSion of my firm,

•

E N G t N ~ E R i N G. (d) The r~duction to a minimum of the chance of total

disablement. T.\le machinery consists of a single-screw en~ine driving

a featherin"g propeller, steam being supphed by four Belleville boilers, havin~ a steam pressure of 300 lb. per sq~are inch reduced to 250 lb. at the engine.

F igs. 1 and 2 on pages 510 and 511 illustrate generally the arrangement of the engine. It will be observed that, ca r­ried upon one bedplate, there are two high-pressure, two intermediate, and two low-pressure cylinders, acting on six cranks. Thehigh-pressure cranks areopposite and adjacent to one another, the intermediate cranks are also opposite and adjacent to one another, and 240 deg. in ad vance of the high-pressure cranks ; while the low-pressure cranks, also opposite and adjacent, are 240 deg. in advance of the intermediate cranks. Each higb-pre~sure cylinder is pro­vided with its steam s top-valve. The forward high-pres­sure cylinder exhausts into the forward intermediate

COMPARATIVE CURVES Of VIBRATION fORCES FOR TWIN SCREW CRUISER OF 30,000 1.H.P.

fuJ,es cmt6tru.cJ:..e.d.J fur JZO Rev~ per~. . - -· -- r~Furce-------FQT"Ci'/ uf~ Coup~ o:pres~ as Tuns a.veruLCen.lres. Fig.6.

-- ...... r .................. . VERTICIAL I I

........ ,.. ,.. , FOR ES.

~· ............... ' ~~ ~ -~. / __.,.. ...... ...--,... • ,·

...... "" .......... _, I• I

... ___ r-

No Free-Fa 'rc,e, HORIZONTAL FORCES.

~----.-.,pz- - - --"""-" r-----4 t----- ... ____ .... ----I . I

t--- ..... ..... ...

...-- ·..;.c--, .,.,. ...... ,

•

----------

f:"... -------•

~ ---'

1------

, ,·

H.PZ.

GCRANK ENGINE • GEJVERALBAQUEDANO"

TYPE.

~ ,-~-- I .Fig. 7 t-, .... ... , , 'I', ,

" .... , / " / • 0 1-< X z < 11: 0 a.

• :r -/

!.-" ,

/ , .. ,•

---

', ',

' ..... .........

............... ~-

_, .........

---- ----

/

/

_,,"' /

/

" - ----

- -- ---I

• ....... ......... ........ /

I'-. ........... ... -V ... ..... t--... __ _

' ........ / ., / :--., / /

........ .,.-..... ... , ___ ...

------ -- ------ ....... Fig.8. V "X

I"-..

' ......... ~ ,~ .... ...

~ / --........... ......

,../ .... , ...

---

/ :....., ...

............ ~

as· . 6{1• A.LP.

1-:L.P. 4CRANK ENGINE YARROW SCHL/CK

AND TWEEDY

~ H.P.

FLP

---- 1---- -- --lP.

4CRANK ENGINE ORDINARY TYPE.

60' 90 • 120' 1(J(J' 18d' 210. ?AO. 8So' 960~

COMPARATIVE CURVES OF TWISTING MOM£NTS FOR TWIN SCREW CRUISER OF 30,0001.H.P.

6 CRANK ENGINE .G£HE.RAL BAQU£DAHD. TYPE --............ ,

'-....

4 CR'A NK ENGINf

AltO TWEEOY. YARRDW SCH~~

/

4-CR.ANK ENQINE (Jf/DIHARY TYPE.

"" " ""

./

'

/ . •

•

. •

.

•

to lay ~efore t~e Inst itution a. brief description of her propelhng engme8. t The design possesses some novel features.. and the ~rrangementl forms a combination which solves wtth .a constdera.ble measure of success, in a simple ma.nner, and at one and the same time some important P.roblems whic-h have of recent years e~gaged the atten­tton of those interested in the design and manufacture of the P.ropelling machinery for vessels of war.

Bnefly these are as follow : {a) The production of an engine which will work with

economy when dev.eloping a small proportion of its full PD'~er, and .thus m sure in a given ship the maximum radms of act10n.

f (b) '~he elimin~tion, as far as possible, of the unbalanced

orces m the en~me.

h(c) Th~ securmg, aA far as possible, of uniformity in

t e turnmg effort on the crankshaft.

t* Pa.per read before the Institution of Naval A rob i teots.

. ~ reference was made to these engines by Mr. Watts N hts paper on ~' Elswick Cruiser~ '' read last year at the ewcastle meet10g of this Institut:on.

• • • • • . ~

............ - /

I• •

~ ~

MUv. oeloWMR.a:rv - J8·7J; Fig./0 .

... "' "' ~ ./ ~

.

.

•

•

pressure cylinder, which, in its turn, exhausts into the forward low-pressure cylinder; the after high-pressure cylinder exhausts into the a fter intermediate-pressure cylinder, which, in its turn, exhausts into the after low­pressure cylinder. Each low-pressure cylinder exhausts 1~to its o.wn co~denser, this beinf! provided with i ts own a1r and Circulating pumps, the former being worked by levers from the corresponding low-pressure engine, and the latter being the ordinary centrifugal type. There are thus acting upon the crankshaft virtually two indepen­dent three.cylinder triple-expan~ion engines of equal size. the cranks of which are alternated with one another.

We will consider shortly some of the leading features in the arrangement.

Ibis unnecessary to remind members of the uneconomi­o!l'l performance of an engin~ w~e~ doing a small propor­tiOn only of the full work wh10h It 1s designed to perform, or of the ex travagant cost of the last knob, or two in our fast ~ruisers, or of the comparatively rare occasions upon wh1ch such vessels are called upon to exerb their full power. This problem of economical propulsion at low powers has been dealt with on various ooca.siona and in various waye. In H .M. S. Alexandra, built about

1875, small auxiliary condensing engi~es were fitted ~o turn the .main shafts by means of gearmg when the sh1p was under sail.

Sir John Durston, in an interesting pa_per entitled "Some Notes on the History, Progress, and Recent ~ra.o­tice in Marine Engineering, " read before the Institutwn 111

1891, makes reference to various arrangements of pr_o­pelling engines which have been fitted more recently In the R oyal Navy, with a view to economy at low powers.

In the General Baquedano it will be seen that, by dis­connecting and securing the bottom ends of the connect­infl' and valve-rods of one set of engines, the other set can still drive the propeller, and do so with an ~conomy equal to that which i3 attained in the best mercantile marine p ractice, the cylinders being proportioned with this object in vie w. The sp eed trials of this vessel consisted' of (1) a six hours' run at full power, a.nd (2) a thirty. pours' run at three-fi fths full power. On the full-power trial she steamed 13.75 knots with a mean of 154 revolu-· tions per minute. At the conclusion of this trial the turning gear was shipped, and within an hour from that time tlie vessel was under weigh again, steaming with one set of cylinders only, the bottom ends of the disconnected rods being secured by means provided for the purpose. Comparat ive trials of the vessel, a t the same speed, under the two conditions of working, viz., with three cy tinders and six cylinders respectively in operation, were not made, as t he time at our disposal was limited. These were vostponed until some convenient ocl asion after the commiSsioning of the ·vessel, and I regret I am therefore unable to place the results before the Institution.

It may be noted in passin&' taatl in the case of the vessel under consideration, wh10h is fitted with a feather­ing screw, it is possible, by reducing the pitch, to develop half power with one set of cylinders only working; but in vessels fitted with ordinary screws, and with two engines on one 8haft, the proportion' of power which can bo developed under this cGndtt ion is of necessity less.

I am not aware of any published results of trials carried out in such vessels, with the view of determining the relative economy under the two conditions; but it would al?pear to be a direction in which experiments might With ad vantage be made. This corvette is, it will be obse~ved, of oomJ>aratively low speed. A cruiser whose maximum speed 1s, say, 23 knots, would probably steam S~bout 19 knots with half the cylinders 1n operation, a SJ?eed which is as high as, or, probably, a great deal htgher than, would be demanded from her under ordinary circumstances. I do not, of course, suggest that with this arrangement the operation of connecting or di~connecting is one nominally of a few seconds' dura.tiOn, suo? as wo~ld be t~eoretically obtained by the mtroduotwn of a d1sconnectmg coupling between the crankshafts of two e~g~es, one being placed forward of the other ; or by dr1vmg back a set of crank coupling bol ts, . both of ~hich are. us_ually delicate and may be vexatiOus operatiOns, but 1t 1s one which forms a rudi­mentary J>art of ~he ed ucation of the engine~ room artificer • or sea-gomg engmeer. It should be noted 1n this connec­tion. th~t, witli ~h:e .engines interlaced, as it were, the contmUlty and ng1d1ty of the crankshaft are maintained under all conditions of working, and that the main bear ­ings being always in operation, whether one or other or botQ. engines be used, this shaft cannot wear ~ut of tr~th as would be the case were one engine placed forward of the. ot~er o~ th~ shaft, ~nd these bearings are always mamtamed 1n line and m working order. I t is obvious that, should it not be desired to disconnect one engine, but to have all the cranks available for instant service stea:m may ~till conveniently ~e passed through eithe~ engme suffi01e~t to merely lub~Icate the internal rubbing surfaces, and 1n no case would It be desirable to have one set. of engin~ uncoupled under the service conditions wh1c~ prevailed, . for example, during the battle of Santt!l'go, and wh1~h were alluded to by Rear-Admiral Melv1lle, of the Un1ted S tates Navy in his paper dealing with "Triple-Screw Propulsion,,, ;ead last year before this Institution by my friend Lieutenant Nor ton, U .S.N .

As regards the balance of the arrangement, Figs. 6 to 11, a~nexed, show, fo~ purposes of comparison, the forces tendmg_ to produc~ vibratiOn in t hree types of engines, the. designs of w~10h. were prepared fm.' a twin-screw cruiSer of 30,0_00 Indicated lior~e-power, the engines in eao~ case ~unnmg at .120 revolutiOns per minute.

~Ig. ~ IS for a s1x-c~ank engine similar to that de­scnbed. m the p_aper, With th~ six. cranks in operation, t~e cyhnder.s bemg two of 31 m. dtameter, two of 50 in . dia~eter, !l'nd two of 81~ in. diameter, by 48 in. stroke. ·

Ftg. 7 IS f?r a four-cylinder engine balanced on the Y ~r~ow, f?chhok, and ~wee?y system, the cylinders being 4~ m. diamete~, 71 1n. diameter, and two of 81~ in. dtameter, by 48 m. stroke.

Fig. 8 is f?r a four -.oylinder engine of the ordinary type, the _cylmders bemg of the same dimensions as in the precedmg case.

The curv~ for the six-crank engine compare very favourably wtth th~s~ of the. four-crank engines . With reg~rd to th~ oond1~10ns. wh1oh prevail when one set of engme~ only IS workmg, It may be remarked that under th~e otroumstances not only are the reciprocating weights very much smaller than would be the oaBe were one engine capable of developing the · full power used to dev~lop the .low power , but the cranks of the disconnected engn~e act -1!1 some measure as balance weights for the worlnng engtne.

, A similar comparison of .th~ twi~tin~ mo!llents on the mankshaft for the same engmes 1s g1ven In Figs. 9, 10, and 1~, ~nnexed, an.d shows at a glance the very marked s~perto~Ity of th~ SIX-crank ? esign in this respect.* In F1g. 9, ~. e., the Six-crank destgn, the loads on the crank-------------·--------------------- - -

* I am indebted to ~1essro. Hawthorn, Leslie and Co. for these ourvee. ' '

pins are equal. In Figs. 10 and 11 the loads on the low­pressure pins are half those on the high-pressure and mtermedi9,te-pressure pins, being the proportion fre­quently adopted in this ty pe of engine.

The following Table gives the total weight of the en­gines, the weight added to produce the balance shown in the plate, and the len~th of engine-room in the three types of engines.

Total Weight in I

Length of Design. Added Eogine-ltoom. Weight. Engine-Room.

tons lb. f t. • m. Six·orank • • • • 1010 5600 6i 6 Y arrow, Scblick, and

Tweedy .. . . 976 9826 6i 6 Ordinary fou r·ora.nk .. 975 9800 67 6

The length of the engine· room is the same in each case ; but we ought not to overlook the fact that, had link motion been adopted for working the valves, the length of the engine-room in the six-crank design would have been greater than that given in the Table, unless, indeed, certain of the valves had been arranged ab the back or front of the engine, n.nd operated by means of lever3 in the manner which has frequently been employed both in the Navy and Merchant Service. The type of valve gear adopted lends itself very readily to the arrangement, the weigh shafts, one on each side of the engine, being con ­nected by a link, and worked by one reversing engine.

In order to counterac t any possible tend~ncy to set fast on the part of the disconnected gear, if disconnected for a lengthened period, the securing gear is so arranged as to permit of a limited motion being given to the various parts. The h andling of the engines, whether t hree or six cylinders are at work, is performed with the same ease as in the case of any ordinary triple-expansion three-cylinder engine, one or both engines being worked by the same regulator and reversing engine. It has been previously stated that an independent steam shut-off valve is attached directly to each high-pre..'lSure cylinder.

In an arrangement of t his nature, the p iston-rods, con­necting-rods, &c., and their accessories are duplicates throughout, unless the two engines are designed to develop differen t powers when working t ogetqer . It is advantageous, a lthough nob essential, to have a separate condenser and air pump for each low. pressure cylinder; not only is the independence of each engine thereby more f ully maintained, but a greater command kept over the temperature of the feed water is secured. As a matter of fact, in the General Baq uedano valves were provided a.t the request of the Cbilian Commission, which enabled each condenser and air pump to be used for either en­gine. Alternative arrangements of cylinders are obvious. Fig. 3, page 510, shows in outline the cylinder tops in the case of the General Banquedano, Fig. 4 shows another arrang.emcnt, and Fig. 5 still another . The latter is the arrangement adopted in the case of twin-screw engines of 16,500 indicated horse-power for the Russian V olunteer Fleet. JY!essrs. Hawthorn are at present engag-ed in con­structing these en~nes, and we have others m contem­plation. It is ma.mfest that quadruple· expansion engines may b e dealt with in a similar manner to that described in this paper, thus forming eight-crank engines.

JYiy firm has recently, with a. view to economy, pro. ceeded on somewhat similar lines in connection with the steering arrangements of some of our large cruisers. These are fitted with two steering engines ; but, ins tead of making these engines du~lica.tes, we have provided dif­feren t sizes, a la rge engme for use when the vessel is steaming at the h igher speeds, and a small eng ine of only sufficient size to do the work when the vessel is cruising or s teaming with a limited boiler power.

I have endeavoured in the foregoing remarks neither to magnify the advantages nor to minimise the disad­vantages of the a rrangement described .

GoLD IN THE TRANSYAAL.-Tbe outbreak of war between Great Britain and the Transvaal early in October con-6idera.bly reduced, of course, the production of Transvaal gold last year. The aggregate output for the twelve months is re turned ab 4,069,166 oz. , as compared with 4,295,602 oz. in 1898; 3,034,674 oz. in 1897 ; 2,281,874 oz. in 1 96 ; and 2, 277,635 oz. in 1895.

Bt.\.ST-l!.,unNAC~S I N 'l'HE U NrrEn ) '1',\.TE~. -The number of blast -furnaces in opera tion in the U nited S tates a t the commencement of F ebruary was 296, as compared wi th 244 a t the commencement of August , 1899; 195 at the commencement of February, 1 !.>9; 187 a t the commence­ment of ... \..ugust, 189 ; 184 at the commencement of February, 1898; and 152 at the commencement of A ugust, 1897. The weekly productive capacity of the furnaces in blast at the dates named was as follows : F ebruary, 1900, 298,014 tons ; _\.ugust, 1899, 267,672 tons ; F ebruary, 1 99, 237, 639 tons ; A ugust, 1898, 206,777 tons ; F ebruary, 1898, 228,338 tons; and August, 1 H1, 1G.>, 37 tons. In the weekly productive capacity of 29 ,014 tons standing to the credi t of Febr nary, 1900, coal and anthracite fur­naces figured for 290,010 tons, the balance being repre­sented by charcoal furnaces. It will be seen that the productive capacity of A mer ican blast -furnaces has now been carried to nearly 300,000 tons per week, or about 15,500,000 tons per annum . The stock of pig sold and unsold in the U nited States at the commencement of F ebrua.ry was 148,336 tons, as compared with 137,346 tons a t the commencemt'nt of J anuary, 113,693 tons at tbo commencemen t of D ecember, 111,5-13 tons a t the com. mencemenb of rovember, 120,541 tons at the commence­ment of October, and 137,821 tons ab the commencement of September. " tocks have accordingly increased to a modera.te ex tent during the last fi ve mon ths.

E N G I N E E R I N G.

ON AERIAL LOCOMOTION.* By HENRY WILDE, F.R.S.

VARIOU attempts ha ve been made at different times to establish relatiOns between gra vity, electricity, and magnetism, with the object princirally of t ranspor ting bodies from one place to another through the air. The author referred to several of these endeavours, and de­scribed some experiments made by himself some years ago, on the discharge and reactive force of elastic fiuids, when subjected to the influence of electricity and mag­netism, as well as under ordinary conditions with the same object in view. These experiments p roved con­clusively that the reactive force so produced cannot, under any circumstances, be utilised as an ascensional motive power in aerial locomotion. Science, hQwever, p rofited by these researches, a.s the velocity with which air of atmospheric pressure rushes into a vacuum was determined, and other results of permanent value in the dynamics of ela-stic fluids were also obtained. The author described his experiments on the ascensional power of aerial screws; but the results obtained were not sufficiently p romising to induce him to proceed far in this direction. His confidence, ho wever, in the ultimate solution of the problem of a viation still remains unshaken. The fac t that man has been able to transport himself through the air westward to Ireland, eastward to and from the Continen t, and has reached a height of nearly 7 miles above the surface of the earth, is sufficien t encou­ragemen t to inspire inventors to further effor ts, till the object of thei r ambition is attained .

In a brief summary of the history of aerial navigation, from the time of the invention of tbe aerial screw and of the parachute by L eonardo da Vinci in 1500, the author emphasized the fact that a flying machine has not yet been created sufficiently energetic to transport a man from one place to another, as in ordinary balloon practice. It was also pointed out that the most recent experiments for navigating the air are mere repetitions of those already known, and manifest a st range d isregard of the f unda­mental conditions which must be fulfilled before aviation can take rank with man's achievements in locomotion on land and on water. These conditions or criteria w~re summarised as follow: {1) A n aviating machine should have power to ascend and descend at any place and at any t ime, under ordinary cond itions of wind and weather ; (2) it should be able to move in any direction, or remain stationary above the earth ; (3) the machine should contain within itself an automatic principle of safety by which, in the even t of any accident to a vital part of the mecha­nism, the descen t would be effected without danger to the aviators. All the means so far devised for navigating the air fail to satisfy one or other of these essentia l con­ditions. oaring aeroplanes fai l conspicuously in all the3e crite,ria, partaking more of the character of pro­jectiles or aerial torpedoes than of a means of loco­motion. Mr. Hiram Maxim is disposed to view the result of his recent magnificent ex periment in this light, and has even proposed that his :tpparatus shall be used as a military projectile.

N one of the means so far devised, from the time of L eonardo da Vinci, is competent to solve the problem of aerial locomotion in accordance with the conditions above defined; and , with one exception, the category of possible solutions is exhausted. In the absence of the discovery of some new property of matter, the remaining method by which the problem may iu the future be attacked, is to reverse the action of a parachute by a vibratory motion, produced by a motor of some kind; to cause the rarachute to rise against the action of gravity, i nstead o using it solely for the purpose of descending towards the earth, as heretofore. Several means were indicated by which this vibratory movement may be effected. When the power of ascension is once attained, t ravelling through the air in a horizontal direction is a comparatively minor problem, a.nd may be brought about by inclining the vibratory parachute from the perpendicular, in the direc­tion of motion required by well-known mechanical means. The sustaining s urface of the para~hute would be suffi­ciently large to enable the aviators to descend with safety, in bhe event of the sudden failure of the aviating mechanism.

RAIL\VAY CONSTRUCTIO IN NEW OUTH \VALE AND CHILL

AT the ordinary meeting of tho In~titution of Civil Engineers, held on T uesday, A pril ~~' ir D ouglas Fox, I residen t, in the chair, two papers were read.

The fi rst of these, on " E conomical R ail way Constnlc­tion in New outh \Vales," by H enry Deane, 1\I.A., l\1. Inst. C.E., dealt with the circumstances which de· mand economical railway construction of standard gauge, in t he interior of New outh \ Vales, t racmg the steps which lead to the adoption of the presen t type, and giving some particulars of the pha.ses which the design of permanent way has passed through since railway con· truction was started in the colony in 1833. The fi r t attemp t to introduce a light railway system

was sta ted to have occurred in 18 4, when money was voted to build a line 340 miles long from F orbes to \Vilcannia, but action was confined to ordering a certain por tion of the steel rails req uired. The author referred to the present administra tive system introduced in 1888, when construction and traffic management were pla.ced under separate authori ties, and the Railway Commis­sioners, wi th the la te 1\Ir. J~. JYI. G. E ddy a t their head, were appointed. In 1894, the author visited America and Europe, and after inquiring in to many different methods, concluded that in the U ni ted S tates was to be

- -* A bstract of a paper read before the Manchester

Literary and Philosophical Society, April 3, 1900.

[APRIL ~0, I 900.

found the type likely to l.ead to the best results in thi colony. A short c~m{>artSon of . the two countries was made, and a descn pt1on was g1 ven of the design fo earthworks and permanent way which bad since bee~ adopted .

T his ~esig:n involved the use of GO.lb. flat-bottomed steel rails. w1th 14 sl.eepera to the 10-yard rail, and dis­pensed wtth ballastmg, the water falling on the surface of the road and ~mbankment being made to run off quickly by proper slopmg toward each stdeo. The author then gave a sho~t account of ot?er economies adopted in water­ways, fencmg, le!el crossmgs, station buildin~, &c. The c<;>st of ~everal hn~. constructed on this pnnciple was gtv.en, Wlth the a.dd1t100 for comparative put:._poses o[ the est1mated cos~ of the P ark to Condobolin Railway, the figures. of wh10h were closely adhered to in the nctual execu tton. The value of the principle wa hown by the fact that .the maintenance of these lines only cost about 30l. per mtle per annum.

I !! c~nclu ·~on, the author stated bia opinion that the savmg m cap1tal cost over the older methods was between 1500l. and 2000l. per mile.

The sec~n~ paper, on "T~e TocoJ?illa Railway,'' by Robert St1rhng, 1\-I. ~nsb . . C. E., de cnbed a raHway built to <;>l?en up th~ ext~ns1 ve mtrate of oda deposits of Toco, Chtlt, a contmuat10n to the south of the famous nitrate fields of Tarapaca.

The special feature of the railway was the sharp curves many of them of only 181 ft. radius, and the de .. ign waa made with a view to employing the heaviest type of roll­ing stock possible for the most economical bandhng of the traffic on the heavy gradients. The railway, of 3 ft. h in. gauge, was divided by the ruling gradients into four sec­tions, of which the firs t, from the port to Barriles, at mile 17, presented the greatest difficulties in con ·tructi•.>n and working. This section had a practically uniform frad1ent of 1 in 25, and almost continuous curves, severa of the sharpest being through more than a emicircle, and between many of the curves there was only 24 ft. of straight line. T he greatest care had to be taken to keep the curves in shape, and the wear of the outer rails was . .

excesstve. "Meyer " locomotives were adopted on this section.

They were built in 1893, and were the first locomotives of this class built in England. teel cars, with channel­section steel frames and corrugated steel sides, were em­ployed, and gave a ratio of paying load to dead weight of 3.6 to 1. The rolling stock was fitted throughout with automatic vacuum brakes, as well as band-brakes, and cast-iron brake-blocks. A vacuum of 12 in. wa.'i found sufficient to control a train weighing about 125 tons on the 1 in 25 gradients.

The country through which the line passes being ablo­lutely devoid of fresh water, all the water used had to be distilled from the sea, or from the brackish water of the River Loa. Lime was added in the ratio of of 1 lb. to 1000 gallons of water, to prevent corrosion. The water was pumped through steel pipes to a reservoir tank at the summit, and to intermediate tanks. The autho~ con· eluded that a rail way with sharp curves could be equ1p~ with relatively heavy rolling stock with economy ID

capital expenditure and in working costs.

AMERIC.\.N Loco~IOTI\'E .- The Erie Railroad Company has placed an order for eight passenge~ locomotives and 25 freight locomotives, which will wetgh 90 tons each without their tenders.

Ao TRALASIAN GoLo.- Tbe production of gold in A~s· tral~ia last year was 4,458,805 oz. , a.s compared wtth 3,542,064 oz. in 1898. The total of 4,458,805 oz. repre­sen t ing thb production of. last year was made up as follows: Western Austraha, 1,643,876 oz. ; Queensland, 9!7,227 oz ; ictoria, 862,4ll oz.; New South \Val~e, 509,418 oz. ; r ew Zealand, 385,773 oz.; T~maDl'l, 80,100 oz.; and uutb ustralia, 30,000 oz. ~be mcrea e in the gold production of \Vestern Austra.he. last year was 593, 692 oz.

D UNEDIN (N.Z.) TRAM\VAYS.-Neg9tiatio~s l?etween the Dunedin City Council and the Dunedm C1ty anbd Suburban TramwR.ys Company for the purchase by t e council of the company's propertr , have bet-n practu:~lly concluded. ubject to the sanct1on of the. local legis1:­ture and the ratepayers it has been dectded that ib e council ~hall purchnse the tramways at 45,000/.b . r conve~ion of the present service in~ one of mech .a~tcis traction- the gas motor system bemg that w. to if favoured-will cost a t least an equally large sum !

11and b

they approve ? f the tra.nsa~tion, the ra.tepape'&~ rr~o )~ ably be requued to sanction a loan of ~00, · ill anticipated , however, that the purchase, If effected, w yield a handsome return.

THE CRAMPS.-T be pla_n_t -of- the C.harles ~illmb~ h ~~~ and E ngine· Building Company, of P h1ladelphia, b 1~ by been idle for more than two rears, ha l?eenBp~ld' ~ Com· Williara Crn.mp and on's htp and Engme· w 10oool in pany. The purchase price, it lS understOod, wash~d by the cash. The proper ty is subject to two mortgages e ec· Clyde Steamship Company for 10,qOOl. a~d 3000l. rdspfor t i vely .. The plant. includes a mar.me ra~w};~il~~ shops immedtate operatiOn, and . macbme .an ttern bo~ equipped with modern appliances, be tdes pa 'd and and a mould loft, together with a ~~!-rft 42 if;e~a:J lies extending into the Delnware for .. >.> • d b the firm alongside Crnmp's dry dock, and wtll ~ uae · Yard and for repair, thus greatly relieving t~c!r mTb/ Hillman giving the Cramps much n~ded fac tttes. since on the shipyard suspended o~ratlons btwof yedars of the enter· death of Mr. Charles Htllman, t e oun er

• pnae.

•

a a

APRIL 20, 1900.]

INDUSTRIAL NOTES. · OF all the industrial sections into which labour is

diYided, none have been mor~ di~oult to bring into line by organisation than shop asststants.. ~hey were among those who condemned trade umomsm, often sneering at its leaders, and holding al,~of . fr?m all combination movements, and yet the pnnmple of associative contracts " is as applicable to them as to others. About a quarte~ of a cent.ury ago a mo:re­ment wo.s inaugurated wtth t he obJect of promotmg some form of associative effort, but it miserably failed, and the one man who became prominent in the work had to pass through the usual form of martyr­dom of all pioneers. Some 10 years ago the move­ment was revived, and the later effort has been so far successful that its ninth annual conference has been in session in the City of Bristol during this Easter holiday season. The hop Assistants' Union is not as yet a great industrial force, but its annual income has increa<Jed from 7151. in 1893 to 3347l. in 1898, and to 5289l. in 1899, while t he balance in hand after pay­ment of all expenses has increased from 21 7t. in 1898 to 3316l. in l 99. This Easter Conference has been in a sense, international, for a representative fro~ t he National League of 1 hop Assistants in Belgium was present a t the gathering. Shop assis­tants are benefited by t he Factories and W orkshops Acts to a certain extent, but there are matters which do not come within t he scope of these Acts, as, for example, the question of board and lodging, which the employes regard as part wages, but which the employers dispute. This matter is now before the Courts, on appeal, and the decision is looked forward to by the employes as of importance. I t arises in cases of dismissal, the assistants claiming compensation in lieu of board and lodging for the period of notice. The union rely a good deal upon legislation, the Shops Bill now before Parliament being described as their charter.

•

- ---The Amalgamated Engineen' Jott1'nal reports that

there is an increased of members from 85,248 last month to 85,529 on April!. Of the total there were on donation benefit 1655, a decrease of 33; on sick benefit 2373, a decrease of 494 ; there was an increase of superannuated members from 3547 to 3557. It is the latter tax that leads so many to indulge in the hope of some State pension scheme. As regards wages movements the report states that, ''on the whole, matters are running pretty smoothly." The disputes have been practically nil. That at Yarmouth was mainly in connection with the team Engine ~1akers' Union, and resulted in an advance of 2s. per week in wages. The pat ternmakers' dispute in Leeds is briefly adverted to, the statement being that the men " struck work for an advance which they had vainly tried to get by negotiation. " The council express '' much regret that the vote on Parliamentary representation is extremely unsat isfactory, only 3597 members having taken the trouble to vote at all, 2897 being in favour of affiliation to the Parliamentary Committee, which was formed as a result of recent. conference, and 702 against that course." In consequence of the small vote and of other matters pending, the question is to be submitted again to the vote at a future time. The benevolent levy of 3d. per member was carried by 8477 to ~2 ag~inst . . T~e council have appointed members m vartous d1stn cts to be on the Federation Committees until the delegate meeting shall deter­mine as to the representation and election of such delegates, defining the position. In reference to "shirkers," the report says : "We have got rid of some of these during the month," and the branches are ur~ed to help the council, for while they are on donat10n benefit, they are qualifying for the super­a:nnuation benefit, thereby imposing on the funds for life. Efforts are being made to deal fairly and honour­ably with members from the seat of war, J ohannes­b~rg and Kimberley, whose clearances cannot be ob­tamed at present as the books are impounded some­where in the Transvaal.

The April report of the Friendly Society of Iron­founders of ~ngland, Ireland, and Wales expresses the congr~tulat10ns of the council on having entered on th~ nmeteenth thousand of its members, the total bemg 18,108. It ~ook 5! years to pass from 11>,000 to 16,000, a yea~ ana eight months to pass to 17,000, and a year and mne months to attain 18,000. The casb balance ha~ also grown from 73,17 4l. 1s. 5d. a year ago, to 96,428l. 13s. 2d. at the present time. The total num~~~ of members on the funds was 1822, a decrease of Hr ... m the month. Of t hese, the total on donation benefit was 337 - increase of 11 ; on sick benefit 544-deorease 126; on superannuation benefit 869- in­crease 16; out oi work and out of benefit 70- de­crease 5 ; and on dispute benefit only 2-the same as last month. The total cost of all benefits was ;80l. 4s. 6d. per week, or 7f d. per member per week.

he cost .of superannuation is 3~d. per mernber per week, of s10k benefit 2}d., of donation benefit l ! d. per week; the latter is a. very low level, for it includes

•

E N G I N E E R I N G. disputes as well as those unemployed from all other causes. The returns as to the state of trade are almost phenomenal. The votes of the members have decreed that the benefi t guaranteed from the Trades Federa­tion shall be in a.ddition to the dispute allowance from the un ion. An accident levy of 1s. per member for the year has been agreed to, payment in four quarterly instalments. The sum of lOOl. has been presented to a member of the South • hie1ds branch, who lost his sight by an accident .

The monthly report of t he Associated I ron Moulders of Scotland is able to congratulate the members on an encouraging increase in numbers, and a gain in the month of 559!. s. 6d. in funds. At the end of the fi rst quarter of this year the total funds in hand amounted to 63,524l. 12s. 9d., or about 8t. l 3s. 2d. p E\r member. This is a very high average indeed for a trade union. The cost of benefits and of management is lower than usual, so that the balance increases. The cost of idle benefi t in the month was 614l. 16~. 8d. ; superannuation, 497l. 4s. 8d. - the former is less, the latter is more, than in the previous month. Super­annuation in this union now amounts to 124l. 6s. 2d. weekly. Funeral benefit in the mont h was low, only l76l. 13s. 4d.; in the previous month it amounted to 3 Ol. The report states that there arc indications of a falling off in t he volume of trade; but it is regarded as temporary, and it is expected that the next report will show up better in this respect. This union is bu~ily extending its organisation by local propaganda; the first of a series of meetings beiug held in Edin­burgh, which is described as a thorough success. Other districts are to hold meetings so as to strengthen the society wherever it is possible to do so.

---The report of the Amalgamated Society of Carpen­

ters and J oiners shows a larger number on donation benefit than in previous reports of the two last years, but t he propor tion is not large. There are 62,407 members, of whom 16 7 were in receipt of donation benefit, 1426 on sick benefit, and 857 on superannua­t ion allowance. At Aberdeen a strike has taken place to resist an attempted reduction in wages, and the employers have modified their demands, which the men refuse to agree to. The council regards the attempt as unjustifiable, and offers the united support of the society in resisting it. I t appears t hat in some oases members have been led to seek work through advertisements in newspapers, and have then found that a dispute existed. Local secre­taries are advised to look out for such advertisements, and caution members against them, so as to saYe dis­appointment and expenses. A case is given in one of the branch resolutions of men signing the vacant book in the morning of a day, then doing night·shift work, and worked on for five days, or rather nights, and then signed on for the day on which the job ended. The secretary refused to sanction payment, as they had five full nights' work, equal to 7! days at time-and-a­half. The council has upheld the action of the secre­tary. The cost of legal expenses in connection with the Employers' Liability Act for 1899 has been 44ll. O.s. 4d. The society undertakes ca~es where they think the member has a r ightful claim.

The principal quarterly meeting of the South Staf­ford shire and East Worcestershire iron trades was held in Birmingham ou Thursday in last week , at which no alteration was made by the leading firms in the price of marked bars, which remain a t llt. 10s. per ton. This is !Os. higher than at the previous meeting, and 3l. per ton advance on the price of a year ago. The unmarked bar makers advanced their rates, 5s. per ton, to l Ol. 15s. per ton; the Eame class of iron a year ago was purchasable at from 6l. 15s. to 7l. !Os. per ton.

In the Wolverhampton district there are no indica­tions of a slackening off in the iron and steel trades, plat es, hoops, strip, and best thin sheets being in great demand, with prices tonding upwards. Pig iron has again gone up in price. In the Birmingham district only 14 members of the Amalgamated Engineers are on donation benefit , and in the 'Volverhampton district only one.

---In the Lancashire districts there is a strong upwartl

tendency in prices, pig iron going up from 2s. to 2s. 6d. per ton , while for finished iron the tone was strong, t hough consumers were holding back except for pressing present requirements. The recent ad­vance of 5s. per ton for bars has led t o an advance in some kinds of finished iron, and some kinds of steel material were also adva.noed.

---11he ''Labour Conference/' which opened on Good

Friday, in Glasgow, could not have selected a better city for its discussion on municipal goYernment and t rading. The delegates present represented both t he trade union and th~ socialist elements, and the Lord Provost was present, the chairman declaring that it was '' the first occasion upon which the Municipality had

:

been officially represented by a Mayor or Lord ProYost. " His lordship said that it was not necessary t hat he should adopt every item of the programme put for­ward, but he offered them a hearty welcome, as earnest men and women who were addressing themsel':'e~ to the consideration of important social and munlCJpal questions.

The strike of r ivet makers in 1 taffordshire has ended in a compromise. The men demanded an advance of 15 per cent . After a month's strike, t he employers offered to concede 12! per cent . This offer was accepted by the men.

The foundry Jabourers in the l{eighley district have succeeded in obtaining the advance demanded, so that the dispute is now ended. . .

The malleable ironworkers in the Lanarkshire clts­tricts have been conceded another aP.vance of 5 per cent., which will affect some 4000 workers. This uow makes a total advance of 50 per cent . in wages during t he last t wo years, and is att ributed to the operation of t he Conciliation Board.

The dock labourers' strike a t :Middlesbrough has been so far successful that the employers have con­ceded an advance of 6d . per day, instead of le. , as demanded by the men, which the latter have accepted .

The carters in the Manchest er district have obtained some concessions as regards overt ime and stable duty, thus ending the dispute. I n Glasgow, t he carters are demanding an advance of 10 per cent . in wages, in · creased pay for overtime, and special arrangements as to stable duty. Negotiations there are pending.

The strike of printers and t ransferrers in the potteries t rade for an advance of a penny in the shilling is not yet settled.

The tramway men in Huddersfi eld are agitating for an advauco of 23. per week, which the tramways com­mittee ha ve r efused to concede. The men estimate that t he increased cost will be about 750l. yearly.

The strike of patternmakers at Leeds has ended in an advance of ~d . per hour, and of 5 per cent. on ovEr­t ime rates.

The joiners at Bridlington, Yorkshire, to the number of about 100, arc on strike for an advance of ld. p er hour.

The strike of joiners and bricklayers a t Taunton cont inues, a bricklayer having been fined 2/. 15s. 6d . for threatening another should he continue at work.

It is much to be regretted that the attempt to est-ablish a Conciliation Board for the building trades has ended in failure; only temporary failure, let us hope. Had it been in existence, a foolish dispute at Liverpool might have been averted. The dispute aro~e as to laying block floors, which the joiners claim to do as a r ight, whereas the masters employ a special set of men for the purpose. In consequence of the attitude of the men, some 2500 were locked out, and it is t hought that at least 6000 men are affected by the issue. It is a mistake t o strike about demar­cation of work.

---Another dispute has arisen in the '~' elsh tin plate

trade. The men demand an increase in wages of 15 per cent ., the employers offer 2i per cent. There is a Conciliation Board, but it appears that there is a deadlock, and a cessation of work is feared.

CANADIAN PAOU'IO R AILWAY.-At the annual meeting of the Canadian Pacific Railway Company, the proprietors will be a-sked to authorise an expenditure during the our­rent year of 3,260,000 dols. for the enlargement of facili­ties at Montreal and Winnipeg, permanent wharves, &c., at Vancouver, improvements in permanent way, addi­tional rolling stook, &c. The proprietors will also be asked to sanction a lease by the company of the Manitoba and North-Western Railway and the Great North-W est Central Railway.

---CA'rALOOURS.- We have received from 1\Iessrs. 'Villiam

llain and Co., of the Loobrin Iron W orks, Coatbridge near Glasgow, a pamphlet showing specimens of struc: ~nral ironwork erected by them at various places. An 1mporta?t feature, an~ one un~sual in catalogues of this nature, IS the approximate pr1ces appended to the dif­fer~nt .types of bri~ges,. roofs, and buildin~s, illustrated, whilst m. an append I~ w1ll be found ta.b1e~ glVing approxi­mate pnces and wetghts of roof prtnClpals of different patt~rns and sp~ns. Th~se should prove highly useful in malnng approxtmate est1mates of projected work.- We have reoei ved from JYiessrs. J ohn vVilson and Co. of 49, Lime-street, L ondon, E. C., an exceptionally compiete catalogue of tubes and pipes, and of steam fittings gene­rally. The pipes listed include wrought-iron or steel­welded pipes up to 10 in. in diameter, and we1dless tubes of still larger dimensions, whilst the list of bevels flange~ and connections for piping is very varied. In 'additio;; to the iro~ and steel tubing already referred to, the firm supply colla of copper and brass tubing for condensers evaporat?rs, and the like, ~well as larger tubes of thes~ ~etals either bra1.ed .or-~oh~ drawn. The riveted pipes ~1sted r~ng~ up to 30 1n. 1n q1ameter. The steam fittings tllustrated m the catalogue mclude Yalves of various pat­terns, lubricators, and injectors •

•

ON THE INFLUENCE OF DEPTH OF WATER ON THE RESISTANCE OF SHIPS.* By M ajor GIUSEPt'E ROTA, R.I.N., Member.

A S!fJ P in movement th rough a. mass of water the exteneton and _depth. of which is very great when ' com­pared to the dimens10ns. of the ship, ca1:1sea pec~liar ~is­turbances to take place m the surroundmg hqllld whtcb become apparent through characteristic wave m~tion at t~e .surface, and through movements imparted t o the hqUld below, at a greater or lesser distance from the hull I~, instead of considering the mass of water to be indefi~ n~te, w~ suppose it limited in height and in transverse drmen~10ns, the a-bove-mentioned disturbances will then be ~ppre~in.bly modi~ed, a ccording to the obstacle inter­~armg With ~h?m bemg more or less remote from the Immersed ship s surface. That would be the case of a.

• • Pig 1

•C H

M ODE L 3 .

t N G i N E E R 1 N G. Depth of Water.

1 mode~ ma.y be considered t o represent an inde6nite se ·

Ft. of shtps; so that the results obtained may be applied": . .. 55 I the finely shaped t9rpedo-boat up to the bigger ships. . . . 71 '.~;he dta.grams, Ftg$. 1 and 3, below, are the curves of . . . 90 restStance f? r the models N os. 3 and 5 for the depths of . . . 111 1 water speCl fied on each Table. (The similar diagrams . . . 135 for the models Nos. 1, 2, an~ 4 are omitted, being of the . .. . 160 s~me cha.raclier as that rela~mg to No. 3.) The absci.eere . . . 188 gt ve the speeds of t.ransla.t10n of the models, in metres per . . . 218 sec~md, an? th~ ordmates the corresponding value of the . . . 250 reslBtance m ktlogramme~.

Speed of Ship. •

Knots. 14 ... • •• • •• • ••

16 • • • . .. . .. . .. 18 • • • • •• • •• • ••

20 • • • • •• • •• . .. 22 ... • • • • • • • • •

24 • • • • •• . .. • • •

26 ... • • • • • • • ••

28 ••• • •• • • • • • •

30 ••• • •• • • • • • • After having obtained all these different curv~ it wa.s

Bu t these elements do not take in to account an iwpor- e~y to .deduce from them a ne~ s.eries of diagram , tant. factor, vi~, the " size " of the ship. 1\llr. T aylor, g tvm 5, m a ge neral way, the vanat10n of resistance of for mstance, gt ves for 20 knots speed the same depth of each model, corresponding to several increased depths of water for a 15,000-ton vessel as for a 150. ton one. These water , at a~y constant SJ?eed. These diagrams are figures are in t his respec t evidently incomplete. H ence plot~d on Ftg. 2 . . the absm.&re being the depth of the the necessity of practical in vestigation from which we water through whiCh the models are d riven, and the

~ Fl9 .2 . • t~

. " \ .. l'O - q~ . - ,, ., M oDEL 3 .

- RESISTANCE ANO SPEED CURVE S ~· ' "$

"~-~~ RESISTANCE AND DEPTH CURVES -AT D I HEREIH DEPTHS Of WAT E R ' i/ "J AT DIFFERENT SPEEDS .

I

• • • - • \ ~ .. ~ , ...:..._

!A'~ Is. .u~, -

31Jb / •

~ f '

,(.) • I ijJ ' '

- v· (.) I ~· r-/

~ •

117 :~~ • I •

~ ,Cl. /

SP«.d .2 ()(} •eo 7 1

~ -

~ ~ J~ r-.... <~'

~ ~ • SlJ~./80

j ••

• I •

I

~ ~ / I

• J ........ . 160

./ I Ob ~ 0(/

~ I

~ ' HQ

-- - / ~ • I ?.b -

• I_..../ SJ!!!!!!. ' I (.(1 /

...... • _... • ./

•

s er~ . "'YJJ1 pv .J eo - · D ¥tJt, a "' ' -- nu:l.rt'A, --. -IJO I ()(J 120 ~ I«> • 1 #4 Ill# •qq 0 . SQ ... • "#:U ICQ I fl' ~ CJ . ,-- •

• -' , •

• . ~ ~~r~t ~ J7J

Pif1 .3 #l-/' . -I\gA ... . .. ~-~/ MooEL 5 . •

/ M ODEL 5 • ,,~ ,. f 4

RE SISTANC E AND SPEED CURVES •

. '/ -• v , fttSISTAN~ ::.U RVES AT AT Olf"FERENt DEPTHS OF

, AND OEPTH WATER "/

.Jf~ // (f 00 Dlf"F ~ENT SP££ )S

•

~-!}} / '--~ .•,..cd- J lS

- .....

~~~~ ,J ... 3 oo

•

/ ·M "-

. ~ A'") .3 NI ·~ .' _0 ~" ~

.;::::::: / ........_ o&OO ' /

J 1 7.f

r;i/) -~ I i

•

~ I

I/ '

~ V • "-. I

' . '

I .·· I ' . ~ I • 11 SD

•j .. ·;_ et: • 4

n"l ~-z 00

7

I 1 .J .. - ~ -r lj. /

I I • I ~ ............ ,)"'

, I , '

~· , '--b' , .~/

: l 111

' // .JY" ' , f/7

I /,', ./ ' ' ~ t;/ .:!/!:!!!!!!;. l. 61

' p~ ' .... 1 cfJ • '1'7

• ''" ' ~OY ' /

., • • ~ I 7J

' ' \P ........ IH

--~ '- -3

• . / I ~

_;.:---..

...._ _....· " I 11'

s d m.o , - _.,_ pt:r .Je< . / - . "' I D~ of w ~.

,_ lJ oo ~" ~ so lns _..,

'"' I ()b u IJC I T.J ~ «< $SS ~ 7S - lo s" 1 0 0 I ..SO ~«1 IJ.u - , . "

body driven through a canal of narrow section , while a.t could get with sufficient accuracy, for any given size ordinates of each curve the corresponding ~esiatances, sea the usnal case is that of a. ship moving in shallow of vessel and at any given speed, what the deptL of j in kilogrammes, for the same speed of translatiO?· water. water should be in order t o avoid the influence of the A ll these curves of resistance (exception belDg made

Until lately no g reat importance was attributed to the bottom. for model No. 5, with which I will deal presently) show depth of the water where spee~ trial~ of ships were ~arried For. this purpose we carried out a series of t ests a t the the same peculiar feature of a curv~d portion followed out; ther~fore t he results obta:med m the sever~J mrc0:m· I expenm~ntal tank of ~he Royal Docky~rd of pezia, by a rectiline~r one, the .lat ter be1~g t~ngent to th.e stances did not agree, very different explanat10ns bemg Italy, usmg models of d ifferent types of shtps. former a t a pomt, the absetssa of whiCh gt~es the ~IU1Xl· sought for the fact. Stokes Ba.y, where British ships T he following a re the pr incipal dimensions of the mum de pth beyond which no increase of resistance 18 felt used to undergo their speed trials , is only 59 ft. deep ; models : from the influence of the bottom. the official measured mile at the G ulf of Spezia, Italy, In F ig. 2, and similarly for the other models Nos. 1 .• is about 62ft. rleep; the measured miles at Cherbourg 2, a nd 4, we ha ve traced the approximate curves (locnd) a nd B rest are 49ft. 1\nd 59 ft. respectively. It is not an of the p eculid.r depths to which we have just allude · unfreq uent occ~rrence for ships to prove f~ter vessels The ordinates. of these c~1rves are w_hat '!e may call when propelled m deep water thA.n wh£ n dnven threugb ' ' deep-sea reststance, " whlle the abscJSE<-e g1ve the pecu· shallow water, though developing the same amount of liar dept hs referred to. Taking ad vantage o~ the pecS· p ower. l ia.rity of each such curve, the diagrams,_ F 1gs . . 5 to '

In discussing the wave theory, Mr. Taylor ha8 worked were worked out . In these the abs01ss~ give, for out figures giving the depth of water required for any I each model, t he de~ths appropriat~ to the speed, p~ott_ed given velocity to a void the influence of the bottom. The . . . . on the correspondmg ordi nates, tn order tb~t. t e

10:

following is Mr. Taylor's Table: T he experiments consil~ted m .towmg each . model fi:uence of the bot tom be nob fel t as an addttlOnal re Speed of Ship. D epth of Water. through the tank, t he bottom of which, for a constderable ststance.

Knots. ~ ... b. length, has been artificially raised by means of a smooth j These latter diagrams refer strictly to the m?dels. 1° 10 .. . . .. ... . .. . . . 28 timber floor, giving a lim1ted depth of water compared extend them to full-sized ships several corrections oug t 12 ... .. . . . . ... . . . -!0 wit h the unlimited one. represented by the normal con- to be made, such as that for the skin-friction, &c. Anyf

- -----------------------l dition of the water in the td.nk (viz., about 10 fb. ). how, to show a rough application of the fou~ curye~ 0

*Paper read before the Institution of Naval Architects. 1 According to the la w of dynamical similarity, each , F iga. 5 to 8, we have tried to ex tend them to ships simi1a.r

I

APRIL 20, 1900.]

; 0 each model, but having displacements successively in­oreMing up to 12,000 tons.

Thus for anr given displacement A, the depth of.water p correspondmg to those p ~or the model con:ndered were found, these dep ths bemg those app.ropr1ate to

eds of from 10 to 22 knots "correspondmg , to the :~eds v of the model. We ob~aine~ by this proceeding f ur new series represented m Ftgs. 9 to 12. below. a~d applicable to ships similar to each of the models con-sidered.

It will be seen from these cur ves that the peculiar

•

• • • •

0 H OF ...

! . I ''

l

• i •

J .. •

t ...,

.. """""~~ le FifJ 0 (J 0

~ .. M OOEL 2 t

l

i t ' !

Fig .? 0 o• ~ ·--Moo£L 3

~ " -

L , ,..

/ .. ,

V ,. ~ .... Tl .. Fig 0 8 .•

• -~~ .... , M OO El 4

•

I L' / a ...I

/ /

u

/ V

'"""

.

l / V

"'

1/ lt,. Jl lt ... .....

.. l ..

( !nS/ll J

•

(

depth of water, beyond which no increase of resistance is felt by reason of the influence of the bottom, would rise with the diapla~ement, and fall down with the increase of the fineness of the hull, the speed being oonstant in any case. We give some examples drawn from the figures above:

--.Model. L 2. 3. 4. 4.

Displacement tons 12,000 8000 6000 3000 1000 Length • • f to 408 385 361 380 263 Breadth .. , 76.6 67 65 40.3 28 Mean draught

Il l 26.6 21.4 20.2 13.8 9.6

Minimum depth for no change in resistance.

Speed ..

knots n. m. f t. m. ft. m. f t. m. I f t. m. 12 164 47 138 42 108 33 89 27 75 23 14 177 54 158 48 125 32 115 32 92 28 16 200 61 177 64 145 44 125 38 118 33 18 223 68 197 60 161 49 141 43 125 38 2U 246 75 214 65 181 56 161 49 145 44 22 270 B2 283 71 204 62 18~ 56 164 60 24 . . 253 77 230 70 204 62 184 66 26 .. .. .. 227 69 204 62

--To ~onolude these few remarks, we come now to the

fcecuhar case of model No. 5, which, it will be seen, be-ongs to the torpedo-boat type. The curves of resistance

were deduced by towing the model throu~h water at a. depth of 1 ft., 2ft., 3ft., 4ft. 1 in., 5 fb. 2 m., 6 ft. 2 in., and 10 fb., about, corresponding respectively to 32 ft .• 31609 ft., 53 f.t., 67ft., 81ft. , and 125 ft. for a similar ship of

tons dtsplacemenb. These curves are d~awn. i~ Figs. 3 and 4, and show

tba.t, . up to a certam hm1b of speed the function

•

E N G I N E E R I N G.

" speed resistance, ohang~s, as is u~ually th~ CB:Se with ships of ordinary shape, vtz. , the reststa~ce w1ll morease rapidly with the speed. Beyond the limtt referred to the resistance keeps almost constant, till it decidedly falls below that experienced by the ship in deep water.

If we now brace the curves in F igs. 3 and 4, plotting as before the resistance as ordinates, corresponding to the depth of water taken as absciss~, it may be ob­served that, up to a certain speed, we may trace the usual curve locus of t he depths corresponding to the minimum resistance; but beyond this limit of speed the remaining

•

•

•

If we compare the shape of curves A1 At, B1 Bit wi~h that of the resistance cur ves io 1 f t. of water, .as s hown ID Fig. 3, it may be seen (1) that th~ maxtmum value of the resistance on the fir3t portlo~ of the cor~e­sponding curves takes place when the dtfference of tr1m is also a maximum ; (2) that the cur~e for a depth <?f 1 fo. crosses the one for 10 ft. at a pomt corresponcl~n~ t 'J about the same t rim in both oases ; (3) that the ?•mmu­tion of resistance of 1 ft . depth as co~par~d ~~t~ that at 10 ft. is coupled wi th a correspondmg dtmmut10n of fore and aft immeraion.

D EPTH OF WATER AND DI SPLACEMENT CURVES -

• • •

., tJ

MODE L I . AT 0 1 FFERENT SPEEDS . Fig 10

Cl . ,

MODEL 2. •

Fig.9. BQnu!trM .z. ~~ KtJI!GrS

zo L

70

• • 80 mdrotA,<t !--

• -~zz rr.. & '/() • " - 16 tJ() •

. 18 -.. ()~ --- ·• ..

.-:. . - 14-

f • " 1~

I() ~ l4o - •

N

~ I so Jl1 ~

-/ t::=- "''

12 .. 40 l o - -

~be~ ......

r- bo~ V ~ - -

' to :--UJ

,..... l20

•

ltn t () -i ~

"-""" l<tooo ~000 ll.a: 6{)()() 10000 •

000

• • 17coo jgooo d()()() 8 {)UJ IQ ~ a t

U I' MODEL 3 . Fig.11. Fig12

'1 n

MODEL 4 . • •

rto m.t!l:rnl j; o f(-, ~ ~

.'\

lW 2Q

70 rnl"'r'-1

S.2$f. »z ./JJ~§ ~ "'" ~ ,

!R ~ • iJ:o 1 .

1 - 14 ~ !4o

~ --- !If • 16... • •

lfo rA

k ,

I~ • 1n ~ ~~~- •

... f .

~---..

-~ I .....- 10 'I

'i!-f?L ....-_ !!£....- -, •

ID ~

~ iotlOO' ro (){)() a ~(/() G,OOO (J_(}(J(J _,()()() ill

TRIM AN D SPEED CURVES __ , , t051ifF a ;;z; sz:-# 5 , ..

• · MODEL 5 " •

Dra..t.lflM a~/ tJtB- .szern; a7Ut sterrv durw;g f.owi.ng 0

Fifl 18 • • 1.<.; £errh d:ee!/!' }2."! fL:. ~ -

16 6 , -· /

0

_;J- --'\ . 8 - · sww, rUJ» (/.epthJ,. 0 I .-\• - .-•

~~- · -·- B I

• .' ' ·, • - · ------I -·-. .._ -·-i ,............ \ / V" •

/ ' . / __...... •

·" . ~ .z... .• .•

0

()

()

• 0

] . .:.. ·-~~~--·---a· -~ -- ... · - ·- · --- - - · ~ . draughk a(; rost- - · - - - · - - ·- ·--- - ·---·-·

d.rrw,ght,oi, T'I}8 -- ·- --. ' '\ 0

A --·\ \

........... •

-·- A .--" . - . ~

1-.- -.L.-\ / ..... • ·- -- . r-- ·-• t-.... ~ ·-• . . --

V

\ / ~ ·r- ._ A •

/ ·-· ~~~~:nt.() . .. --. . -• • • ~-I'· A, , / . - · '6 ·-.... -

A • ~~.l'uU~o • • ' . . . • • Sped ""~. mdrt:t:J J let'-'«-

t oo t. (f4 !1.()() ~.so fS 3f.l.C)

curves show a minimum corresponding at almost the same value of the abscissre.

To illustrate the above remark, let us consider the case Of the torpedo-boat of 150 .tons displacement; from the curves of Fig. 4 we get the followin~ value of the depth of water correspondin~ to the mimmum resistance for the several speeds considered:

Speed in Knot~ .

12 ... 14 .. 16 .. . 18 .. . 20 .. . 22 .. . 24 .. . 26 .. . 280 .. 30 ...

.. .

...

. ..

...

.. .

...

...

. ..

. ..

...

...

...

...

. ..

.. .

.. .

. ..

.. .

. ..

.. .

Depth, Corresponding to Minimum R esistance.

Ft. JYietres. ... 43 13 . .. 53 16 .. . 76 23 . .. 85 26 ... 85 26

20 (about) 6 20 '' 6

. ..

. ..

.. . 20 ,, 6 • •• 20 '' 6 ... 20 ,, 6

An explanation of the phenomenon we have pointed out, viz. , the decrease of the resistance at high sp eeds in shallow water, may be found, we think, in the variation of trim, which is sensibly different from that observed in deep water. Fig. 13, s hows the variation of trim, as marked down during the experiments carried on with model N o. 5.

The curve A A gives, with its ordinates, the variations observed in the vertical p osition of the aft perpendicular in deep water, at different speeds.

The curve B B, ditto for the fore perpendicular. The curve A 1 A 11 ditto for the aft perpendicular, in

about 1ft. of water. The curve B1 Bh ditto for the fore perpendicular .

~- ()() . l.t.so f.J)() • f.$0 . • - •

It is our opinion that, if models Nos. 1, 2, 3, and 4 were to be driven at rates of speed ''corresponding " to those that have caused the phenomenon of the d tminu­tion of resistance on model No. 5, t he same conclusions ought to be arrived at.

TURNING MOMENTS OF MARINE ENGINES.

On the Uniforrnity of Turnilng Moments of M01ritne Engilnes. *

By Professor Dr. LORENZ.

I N connection with the balancing of the forces produced by the reciprocating parts of marine engines, which, as is well known, are the main source of the injurious vibra tions of the ship's hull, the question of the removal of g reat fluctuations in the turning moments, producing changes in the angular velocity of the crankshaft, has come into prominence. There is no doubtJ that great uniformity of the turning moment during one revolution, in union with the most p erfect balance possible would have an excellent effect on an engine, a.nd would produce a nearly constant thrust of the propeller.

The opinion has been often expressed that it is quite impo3sible to obtain a good uniformity of the turning moments in combination with a good balance of the reci­procating masses. This opinion seemed not to be un­founded, as it was known that the crank angles have a considerable influence on the fluctuations of the turning moments, although the laws of this fact were unknown. While, hitherto, the crank angles have been found mostly by experimenting with the diagram of turning moments

* Paper read before the Institution of Naval Architects •

• •

•

• •

530

of e~ch cy~inder, displacing them relatively to each other, u_nttl a sattsfac tory result bad been arrived ab, the condi­tiOns for a good balance of the moving masses require an­other arrangement of the crank angle , and this may be the reason why the before-mentioned opinion obtained.

I, on the contrary, believe thab I can show by what follows that the balance of the reciprocating masses nob only ag rees well with the conditions for the most uniform possible dia.gram of turning moments, but is absolutely nec~ary for attaining a good uniformity of the angular veloctty of the crankshaft. T o prove this, it is only necessary to lay down a simple formula for the tangential force T . produced by a cylinder (Fig. 1). As after one ~evolut10n of an eng1ne all conditions repeat themselves, 1b res~lts at once that T may be represented by a harmonic funct10n of the angle <P of the crank, viz. :

T = A 0 + A 1 cos q> + A 2 co3 2 <P + . . . + B1 sin 4> + B2 sin 2 4> + . . .

In this formula the constant A 0 is identical with the average tangential force in the circle of the crankpin. The two great fluc tuations of the diagram during each revolution show t hat both coefficients A., and B2 are of much greater amount than all the others . If the con ­necting-rod were of infinite length, the form of the dia­gram would be the same for both halves of a revolution, and therefore all terms of odd multiples of 4> would dis­appear. Consequently, all terms involving 4>, 3 4>, and so forth, originate exclusively in the influence of the finite length of the connecting-rod. It is important! to point out that, in th~ harmo~ic function for the effect of weight, those terms wttb the smgle angle 4> are the greatest, just as it results from the form of the curves in Fig. 2. The rule for the effect of weights is therefore quite different from that for the tangential force, and it is, therefore, impossible to balance the great fluctuations in the tangen­tial forces by reciprocating weights.

The tangential force may, therefore, be expressed by the following simple formula :

T = A 0 + A cos 2 4> + B sin 2 q>. • • (1) If there are other cranks which are leading by the

n.ngle u. relatively to that considered first, we • hall a rrive a t the following expression :

or T ' = Ail' +cos (<P + 2 a ) + B ' sin (2 q> + 2 a ),

T ' = A 0' + cos 2 4> (A' cos 2 a + Bl sin 2 a) -sin 2 <P (A'sin 2 a- Bl cos 2 a ).

The total force for all the cranks is then ~ T ' = ~ A0' + cos 2 <P ~ (A ' cos 2 a + B' sin 2 a.)

- sin 2 <P ~(A' sin 2 a.- B' cos 2 a).

If this total tangential force is not to be influenced by the fluctuation originating from the double angle 2 4>, which fluctuations, as we have seen, are the greatest of all, then both equations

~ (A' cos 2 u + B' sin 2 a) = 0, ~ (A' sin 2 a - B' cos 2 a) = 0

must be fulfilled. The coefficients A ' and B' (assuming a similar form of

indicator diagrams for all cylinders) are proportional to the average tangential force Tm of ea{!h crank; or, if a and b denote constant quantities,

A' = aTmand B' = b T m .

Then the conditions are a :ITm oos 2ct + b %Tmsin2ct = 0, a ~ T msin 2 a - b ~ T mcos 2" = 0,

or, if they are to represent any value of a and b

:I Tm cos 2 a = 0, and l T m. sin 2 rt = 0. • (2)

'rhat is to say: An ideal form of the diagram of the tang en tia,l forces

(or turning moments) of a multiple crank engine is ob­tained, if with the double-crank angle a closed polygon can be drawn, the lengths of the sides of which are pro­portional to the a verage tangential force of each cylinder, or to the work done b y each cylinder. The still remain­ing fluctuations of the total tangential force~ T m., which cannot posstbly be neutra lised, originate from the fact that the diagram of each cylinder does not (in conse­quence of the influence of the finite length of the conecting­rod) exactly follow the rule expressed in equa t ion (1).

The construction of the closed polygon of the average tangential forces is very easy for all practical cases, and it leaves to the designer, without detriment to the balance of the m asses, a wide field for th~ choice of a suitable d is­tribution of work to each cylinder and of the crank angles.

I will now explain the application by some examples. For the three-crank engine with three angles of 120 del$'. (Fig. 3), the po~ygon _sh?ws an equilatera~ trians-le (Fig. 4), that is to say, m th1s mstance the destgner 1s bound t o an equal distribution of wor~. That w_e can ob~a.in, in this way, favourable tan~e~ttal force d1agrams 1s su~ ­ciently well known; and It lS also known that any devia­tion from the equal dis tribution of W?rk ~auses the tan-g ential force d iagram to un~ergo de~no~at10n. .

With the four-crank engme, wblCh 1S of grea~er m­terest for the possibility of balance, the construct10n of the closed polygon of the average tangential forces offers also no difficulty. I presume tha t ~~e crank angles are defini t ively given (Fig: 5) ~y t~e cond1t1ons of the l?alance, as ~fr. Schlick explam~ m hlS paper. W e ~btam, then (Fig. 6) a q uadrangle Wlt h double angles, which m ust be so dra~ tha t the lines re{>resenting the work, cor~e­sponding with two consecut1ve cranks, s tand oppos1te each other. Two of the sid es of the quadrangle may be freely chosen and then we obtain already, t hrough the lengths I., r'r. , III., and IV . . a. useful dis~ribution of work which will ful fil the condttlon of equat10n (2), and 1Vhioh w1 thont CJll e:ition me.y be rnaintained in addition

E N G I N E E R I N G.

to the conditions for balance. N aturally, e very parallel to one of these four side~ will also give a useful d istribu­t ion of work. This leads to the rule that, with a four­crank engine with given orank an~les, the distribution of the whole work of the four cranks IS fi xed as soon as the pro~ortion between the work done in the two cylinde rs 1s gtven.

In practice we endeavour to obtain symmetry, not only for the masses, but also for the distribution of the work of the cylinders in such a way that the work done in each of a pair of cylinders shall always be equal. This is accomplished by drawing a polygon of the tangential forces, which polygon is divided by a diagonal line into two triangles, each having two equal sides (see Fig. 7). As the angles in these triangles are at the points 180 deg.

.- ......

[APRIL 20, I 900.

~ight be inconvenient. . ~or ~hat reason it is much s1~pler to use a:n eq_ual d1strtbut10n of work in connection With two opposite ngh.t an~es of th.e . cranks, which. as is known, agrees well wtth the cond1t10ns of balancing in first order. As . an. instance ~f thi.s case, the diagram of the. s.s. Pamoma IS shown. m F1~. 11, the engines of wh1ch exert 220 h?rse-power 1~ the high-pressure cylinder; 242 horse-power m th~ first mtermediate-pressure cylin· der; 23? horae· power m the second intermediate. pres­s_ure cylinder, and 246 horse-power in the low-pressure cy­lmder ; whereas, the crank anglos are a = 70 deg., {3 - a =. 90 deg., a.?d ~ = 110 deg. Indeed, the work, which is fa1rly well d1stnbu ted, corresponds in this instance with a fa.vou~a.bl~ diagram of the tangentid force, as repre­sented m Ftg. 11.

A ·' ·, _ r·'fJ· .t. / •. ' .,...-- ~ , . ....... . . . ' . ' Fig .:J . / I • / • / . ,

/ : ' / ., / T. ' ·, / 7 '

I • Zra. '- / ., I . il ·, . ;, ' / .

(1. • • ' /tr • · - ~ '~ .I . - -. .... ~" (······f .... .,;

.......-------_____ Fig . Z .

Fie .4 . .,. - .. ~

24Q • ~ .. . \ ; - --~-• . • •

I

Fig .5 .

IV

Fig . 9.

. " . I • 14{1 ..-••

Fifj.10. I V

'-----:------'~···

I

•

Fig .6 .

• • • • • •• •

" ... /

~ ~ ~ ~

11I

....... .,·

Q., ~ ~ ~ ~

~ ~

IV

• • . • •

• •

...- ·-/

/ /

•

' ' ... ., __

• • • •

'

I ·. •

-

• •

,. .. ~ r .,

· 90 .. .. •

.. ... ...... •

~ L . [J

.Fig. 8. --· • . " .- .........

Fig. 7.

••• • •• •

IV

• • •

• ' I

• •• #If • • I

-/ \

. . ' J...._ , • .

I • ~ ....

I I

I

•

. ,._ ... !XI" "" ' I

I

... , ·' ' · -.... \ • \ I " . ._.

' •

' ·-/

ss .... -. ., M ell:Jeruf.tv

~ Cl.. -

~ ~ <;::)

~ ~ ~

\() ~

. ..:1 ~ ~ ~ ........ ~ ~

\

IV • ~

•

• ...... . / • ' ·-·-·' / / ' / • ..... - -/ • / , -.

.,.-.... / '

Fif1.11. , .- ...... -· ..... - · ~· ' ., --..._ . .,..,

, · \ _ Q..,

~ ~ ~ C'l( t\t ~ C'1

~

~ ss N C\l .. ...

cl. 11 pa,nw rua- ••

~ ~ .. ' ...., ~ ~.'1 ..., . , . . ' '

I 11 ID IV

- 2 a, and 2 "' - 180 deg. , and as, a b the same time, the crank angle {3 = o, t he result will be

I . _ II. _sin ("' - 90 deg. _ cos-y - - . Ill. I V . sin (90 d eg - a) cos a

By means of this formula the distribut ion of work for symmetrically arranged four-crank engi nes is fixed. This case is especially important for triple-expan ion engines provided with two low-pressure cylinders. One recognises her e also that , after the proportion of I. : II. or II. : IV. has been fixed, the proportion cos 'Y: cos a can be found . Anyhow, the procedure is extremely simple. As an in­stance in point, I may refer to the dia.gram of the t angen­tial force of the s.s. Medjerda (Fig. 8), where the high-pres­sure cylinder and the intermediate - pressure cyliuder each exert 905 horse-power, but the low-pressure cylinders only 600 and 630 horae-power respectively. The crank angles are a = 64.5, {3 = o = !>4.25 deg, and"' = 107 deg. The condition (3) is here almost entirely fulfilled, and the diagram (F ig. 8) has, indeed, a very sat isfactory form.

With quadruple-expansion engine3 it is desirable to divide the work equally between all the cranks. T o effect t his, t he polygon of the tangential force will become a rhombus ; because each pair of opposite sides must be equal and parallel (see Fig. 10). This means, only that the cranks corresponding to the opposite sides of the polygon must be a t righ t angles to each other. The ratio between the angles a and 'Y is indifferen t, but the sum of these angles must be 180 deg. In case the crank angles are given (see Fig. 10), we are also able t o obtain a good dietribution of work by a. .P...&rallel d rawn to one side; but I ; must ~lwe.f• edual lYit ~nd II. eduL\l III.j whioh

Finally I should like to mention that, in all .the dia­grams wh'ich have been examined by ~e, _and w~ch b':!': taken from English and German penodtcals, .t e a . conditions have s tood the practical test, and, lD partiCu­lar, the diagram of the tangential fo~ce . has. been ,;~~k unfavourable in all instances where a dl.Strtbutton of b bad been chosen without having taken care that t ere should be two opposite right angles of the c~~· hove

F or that reason I recommend the condttlo?S a of explained for the attainment of a favourable diagral!l the tangential force to the consid~r~tion of the ~e~n~ For practical purposes these condtttona may Elo x­suitable because the inconvenient and trou esom~ded. , 1 · · f ks can be a vo1 e , periments with severa. postt lOnao oran . t"ng and there is no fe:l.r that! the balance of t~e reetpbroca. 1nk masses would be disturbed by the altera.t10n of t e era angles.

F RENCH SHIPBUILDING.-A company has been for~fan~i~ purchasing the works of the Frenrch q.eneraldT:Ud:taking Company a t P enboeb, near St. N azaue, an. . the building of ships of war and general sb1ppmg.

T HE SuEZ CAN AL.-The shipping transit revenos o:~~e Suez Canal Company in F~bruary amous~f : d ~66 sooz: as compared with 290, 400l. m F ebruary,If . ' · tb~ first in F ebruary, 1898. The aggregate eo ectlOn 1~red with two months of this year was 545,396l. , as cam~ 549 9741 675, 077t. in the corresponding period o£_1899, e.n • 1

'

in the oorreeponding period of 1898t

•

•

APRIL 20, 1900.]

ON BALANCING OF STEAM ENGINES*. By HEBR OTTO SuHLIOK, Member.

IN my first paper on balancing of steam eng ines, I have shown the possibility of balancing a four-crank engine in such a manner- a connecting-rod of infinite len~th being presumed -as to completely neutralise the vertical forces as well as the couples produced in the plane of piston­rods. As it is, however, well kno\vn,. a disturbance is caused in the balance by the conneotmg-rod; and the object of my further investigation. has. therefore bsen to ascertain up to what extent thts d1sturbance can be avoided. I have extended these investigations to engines of four five, six, and more cranks, and have succeeded in findi~g the conditions requisite for a. complete balance:

• I I

' •

Fig .1. y

A c I c A

., :!o o!

~-t ·--· .....

fo --{!· • •

t1 '

• , ,

, • • • ,·

I I

;!>

I ... :!> t.

!<· - ··· l ·- - - -~

•

........ .:n. ........... ~- --· .. ··--·· I I

,.. • • •

c

• I

r-- --·0 --- ~

t

y

•

~ l ~ + · . •

~ ·.,

J.

' •

•

'

' I ' "'--------- ------- - . ---- ------------~ •

•

)

I •. '

y'

•

~ --- .. !'9 . 9 . '• ,.... ....... _

- ---. . L ... ' "' r--- ... .. ' -a, "".. .. '

~-r---- .... ', ' ' ' ' \ , , :c ' '

\ _'' \ q • • I \ I t

I o I

I c \ I I 0 I

----

•

E N G I N E E R I N G. 53 1

neutralised. The arrangement will then, also, be symme­trical with re~a.rd to the reciprocating weights and to the crank angles. Therefore, the weights marked A (see Fig. 2), or ~nd working on the two outer cylinders, mustJ be equal, ns also the weights C working on the two middle cylin­ders. The angle enclo3ed by the outer cranks, as reprd· sented in Fig. 2, is marked a, and the angle formed by

= tan 2 a. • tan 2 'Y + (tan2~ 2 2 2

+ tan 2 .! ) + 1, ~

tan2 a. • tan2 'r + (tan~ a. + ta.n 2 i' ) = 3. (1.) ~ 2 2 2

the middle cranks 'Y· From (34) follows :

In order to secure a. favourable proportion between the weights A and C, and to make these weights as light ns possible, it is, in most cases, advisable to make the dis- or tance l somewhat greater than a or b. The greater the distance between th6 two inner cylinder3 in comparison with the distance between an outer and the neighbouring inner cylinder, the less will be the difference between the weights A and C. The distances l and L being given,

tan ~ = l tan 'Y 2 L 2'

tan 2 a = l tan a tan ! . 2 L 2 2

In the same way followd from (3.J ) :

tan!! 'Y = ~ tan ~ tan 'Y. 2 t 2 2

•

• . (II )

• (III. )

c

, • ,

, , • I

I ' • :s.

D

A

• • •

• •

c •

D

•

Fi1J .6.

/~' I .' l I

.E

8; 'f

(

I I

•

\ •

]j'

•

0 nl..-.\:--\

-

A

c

',,

I

'

•

' • ' I

• • •

A'

Feg . ll.

~-

'• •• • . '•

n •

I

-

By adding equations (II.) and (Ill.) we get

tan2 ~ + tan2 'Y_ (~ + 1- ) tan ~ tan "Y. (IV.) 2 2 l L 2 2

If (IV. ) be introduced into the equation I., and we put at the eame time

4 t L we have

h = .!. (I, + i ),

tan 2 i . tan 2 ~ + 4 h . t an i . tan ~ = 3. (V.)

Calculating from this equation the value tan i . tan

"Y - ,we get 2

tan ~ tan .2 = - 2 h + · I (VI.) 2 2 '\1 4 h,2 + 3.

:Multiplying this equation by (44), we find

. a. . "Y _ l.+ 1 1... 3 SlD - • SlU - - - " ' '\f ~>· + -.

2 2 4 • (VII.)

If we first add equations (VII.) and (44) of the Ap­pendix, and then take the difference, we get on the left the two expressions

cos 'Y + a and cos "Y - a. 2 2

• Vl Z.,

~h2+ cos "Y + a. - 1 +h- 3 . - - -, 2 2 4

• (VIII.)

and 'Y - a 1

- h + ~ 71 2 + 3 C03 -- - - .

2 2 2 • (IX.)

A fter having calculated the value

h=.!(~ + !:.) . 4 l L • . (X.)

we find from equations (VIII.) and (IX.} without any

difficulty the values of 'Y + a. and 'Y - a, and from these 2 2

we further find, by addition, the value of "'/, and by sub-traction the value of a.. ·

If ~ passes through all values from 1 to ex:, then 'Y l

would range from 90 deg. to 120 deg., and a. ab the same time from 90 deg. to 0 deg., and the ratio

a. cos

c 2 - -- • • • A cos :r

2

(XI.)

would pass through all values from 1 to 2. In designing an engine, we should proceed in the fol­

lowing manner :

I I I I

I I t I -----·- --- -- -- ------ -

\

' ' ' ' ' ' \

' ' I I

' I ~ . , .

I

1 .' .. .. -~ f)' '' .. ---

•

-- a,- -- I --· b -·-•

I • .... __ . ... -

(~341 1 Y!

After the distances Land l are settled, the angles a. and "Y can be ~certained from equations (VIII. ), (IX.), and (X.). The value of C or A can then be got from equation (XI.), when one of the two is settled. U nder A and C are to be understood, as is known, the weights of the reciprocating parts of the ens-ine which are in conne?tion with the cranks. They consiSt of the sum of the wetghts of the piston, of t~e piston-rod,_ the crosshead, tbe_guid&~, and a certain port10n of the wetght of the connectmg-rod. The other portion of the connecting-rod is to be regarded as rota. tin~ with the crankpin, and must be taken into consideratiOn in compensa.tmg for the rotating masses, as thes~ parts. must be compensated f~r seJ>arate~y from the re01proca.tmg pa.~ts. Th_e propor~l<:m m wh1ch the weight of the connectmg-rod IS to be dtvtded between the cross head and the crankpin is determined by the position of the centre of gravity of the connecting-rod. The weights, which. belong to each end, are inv~rsely propor­tional to the d1stance of the centre of graVIty from the two pins: If, in Fig. 3, m, and n den?te the above-men­tioned dtstances of the centre of grav1ty, and \V the total weight of th~ connecting-:od, th~n t~e portion 10], which is to be cons1dered as reCiprocating, 1s equal to

which I shall, perha~, on some later occasion make public.

In the present paper I shall, however, limi b myself to disoussin~ the method of finding the balance for a four­crank engine which is for the moment the type that offers the most practical interest. In~ a. four-crank engine with the most f!l'voura.ble

balance 18 to be design ed, the element~ must, m acco~d­ance with what has been demonstrated m the AppendlX, be arranged in such a. manner that the yertica.l f~rces ~re perfectly balanced, even when taking mto constderatton the influence of the connecting-rod, and that the couples are balanced as far as a. connecting-rod of infinite length would allow. After having fixed the diameters of the oylindel'll, the distances of the axes of the latter can be laid down, which, a.s a condition, must be symmetrically arranged with reference to a. vertical linA Y Y' (Fig. ~), because this was one of the suppositions for the enunCla­tion of our formulm given in the Appendix. Therefore, the distances a and b must be equal and, with such a. sym­metrical anangement, the vertical forces can be perfectly

• Paper ref'd befere the In~'ituOion of Nl\val Arohiteo•sl

all the other elements of the engine are fixed. The con ­dition for the balance of the vertical forces, w~th regar.d to the disturbance produced by. th~ connectmg-r~d, 1s expressed by the following equatton m the Appendtx :

Cos !!:. , COS :1. - .!. 1 • o • ( 44) 2 2 - 2

and the condition for the balance ~f the ti~ting c~upl~s, on the supposition that the conneotmg-ro.d 18 of u~fim~e length, may be expressed by the followmg equatiOn m the Appendix:

a "Y L. tan-=- •

2 2 • • • (34)

As _ 1 _ = sin ~ E + cos2 E = tan2 E + 1, , co32E cos2 E

The equation (44), after being raised to the second power, may be expressed as follows :

4 = 1 . 1 = ( tan2 i + 1 ) (tan 2 ; + 1 )

OGS SI « COS 'l "Y 3 M

·w1 = ~w, A

and the portion which may be considered as rotating as

w2 = ~ W. A

Generally, it is ne~essa.ry to first. fi x th~ weights of A, viz., the minimum wetght of the re01proca.tmg par~ of one of the outside cylinders. Should the two outstde cy­linders be of different diameters, we should fix A for the larger cylinder, and then incr~asA the ~veight o~ the t>hl~Oh of the Other Binaller cwlmdert \IDtl) the wet"hf.91

-

53 2

of the reciprocating parts of the outsid e cylinder3 become equal. -

The slide valves are generally worked by rods, which, in comparison to the throw of the eccentric, are very long. '\Ve may therefore assume, without committing any serious error, thab the motion of the s lide valves follows the la w of the versed sine. Th u~, for balancing the masses in the vertical d irection, the influence of the slide valves is the same as if they, together with the driving rods, were concentrated at the centre of the eccentric and rotate together with the shaft. The slide valves and dr~ving rods can, therefore, be treated to­gether with the crank arms as rotating parts of the engine, the e·ffect of which masses can be compensat ed for by other rotating masses.

Gcoutrt1·ical R elation. bet·ween the C'rank A tlgles and the Di !>tan.res of the Oylinde1·s.- "]\Iy f riend, Dr. Schubert, Professor of 1\'Iathematics, Hamburg, has found out some more interesting feature~ connected with the bala nced four-crank engine, which, I think, are of sufficien b interest to be m entioned hera. F or this purpose we make use of the n otation applied in Fig. 10, in which the weights working on the different cranks are cn.lled A, B, C, and D, and the corresponding crank angles (see Fig. 9) re­presented by a, b, c, and d. In the present case no sym . m etrical arrangement of the cylinders has been adopted, and the distances of the cylinders are to be measured from a freely chosen vertical line in the plane of the axis of the cylinders, and are to be called l 1, l.2, and l:l , l4•

Assuming the connecting-rod to be of infinite leng th, the conditions for balance, in accJrdance with forroulm (9), (10), {13), and (14) in the A pp endix, are as follows:

A sin a + B sin b + C sin c + D sin d = 0 (X u .) A cos a + B C03 b +C cos c +D cos cl =0 (J nr.) A l1 sin a +B 12 sin b + C la ~in c + D l~ sin d =0 (XLV.} A 11 cos cc, + D 12 cos u + C l 3 cos c + D l 4 cos d =0 (XV.).

If equations (X. U .) and (X III.} are multiplied by l1 and subtracted from (X IV. ) and ( .. / ·V,), we get

B (l 2 - l1) sin u-1- C (l3-l1) sin c ~ D (l4 - l1) ~ind=O (XVI. ) B (l2 - ld cos b+ C (l:J - ld cos c + D {l4 - ~)cos d=O (X VII. ).

Ifnow (XVI. ) be multiplied by cosb and (XVII.) by sin b, and we subtrac t and apply twice the formula sin a. cos (3 - cos a. sin (3 = sin (a.-(3), we a.rri ve a t

C (ls - l1) sin (b -c)+ D (l4 -l1) sin (b-d)= O (XVIII. ).

If, further, (XII. ) and (XIII.) be multi plied by l 2 • and as in the foregoing instance subtracted from (XIV.) and (XV.), and if a in the equation so obtained be treated in the same manner as b, then an equation corrE:lsponding with (XVIII) will be the result, which differs from ib only m that l2 take3 the place of lh and et the place of b, and now reads C (l3- ~) sin (c - a)+ D (l4 - l2) sin (cl - a) = 0. (-rL , . ).

If, now, the values for

be obtct.ined from (XVIII.) and ( ... ~ IX. ) and equa ted, we get

(l 4 - l1) sin (d - Z,) _ (l.J - /2) sin (d - a) . (la - l 1) sin (c - b) - U:t -_ l2) sin (c - a)'

from which results that

l4 - l 1 . l~ - ~ _ sin (cl - a ) . sin (c - (() (XX. ) l4 - l2 • l3 - l2 - sin (d -b) · sin (c - b)' ... - · ·

This equation (XX.) shows clearly that t he distance3 of the four p oints ab which the axes of t he four cylinders are to be imagined , have the same twofold relations as the sines of tbe four angles which are formed by the cranks of their extensions. This is, in accordance with synthetical geometry, t.he re~uisite but sufficient condi.tion tb~b the four points m wh1ch the axes of the four cyhnders h e can be brought i nto a perspective position with the four lines extending from a point in the same, or opposite direc­tions of the cranks, i .e., into such a position that these four lines will ru n through the four a xes of the cylinders.

If. now, the distances of the axes of the cylinders A, B C and D be laid out on a certain scale along a straight li~e '(see Fig. 4), and . these fO\lr ~oin ts. are connected with a freely chosen pomt 0 by strMgbt hnes, the lat ter, or their extensions (in Fig. 4) marked 1, 2, 3, and 4, will represent the cra.nk angles requisite to obtain a correct balance, supposing the connecting-rod to be of infinite length. Moreover, it is n~cessar7 that .the reciprocatin~ weights be of such proportion as 1s reqUJred by the crank angles, and by t he dis tances of the axes. This rule will also hold good for the case previously treated by me of symmetrical arrangemen t, where in

A= Band C = D,

and wherein also two opposite crank angles (see Fig. 2) b ecome equal. Ther~fore, the point 0 (F~g: 5) on the axis of symmetry Y Y may occupy any p os1tlon, and yet t he lines A 0, B 0 , C 0, and D 0 will indicate the crank p osi tions which permit of a balance, on the supposition that the connecting-rod is. of infinite length:

If the height of the p omt 0 abo ve the hoe of AB be fixed in such a way that the following equation i n the A ppendix:

a "Y 1 () cos - . cos - = - . . . . 44 ~ 2 2

be fulfilled the resulting a ngles are those which will allow a perf'ect b alance of the ver tical fore~ ~th a con­n ecting-rod of ~efinite len~tb, ~nd of t he t1 lt m g co.uples with a connectmg-rod of mfiUtte length. The pomt 0 and the crank angles et ~nd 'Y can now b~ found by pro. jection, as will be expla10ed by the follow1ng::

T he line A A ' in F if('. 6, drawn to a ce rtam ~cale, shall represent the distance L between the <?Uter cyh.nders, and BB' the dis tance l between the two m1ddle cyJmders, but

E N G I N E E R I N G. in such a way that the arrangement of the cylinders is symmetrical about the p oint M.

Erect on the line A A' at B a p erpendicular line B C. and make A. C, A B ' . Draw at right angles to A C, at the point A, a line which cuts the exten~ion of B C a.t D Then connect the points D and A', and make D E = DB. and erecb another _J:>erQ._endicular line A' F at A', and make A' F = A' E. Take the dis tance B C with the compas~, and with centre F d escribe an arc interaecting the line A A' at G, so that F G = B C. Now draw a line parallel to F G through B' , cutting the prolongation of A' F at H . After having erected a perpendicular line at M:, make l\I I = B ' H . The p oint 0 dividing the dis­tance 1\'I I into two equal parts will be the p oinb sought for. On drawing now the lines A 0, A 'O and B 0, and B' 0 , the positions of th~ cranks a re obtained.

Balaoced E n{dnes 'With Fotw D~U'e1·ent W eights of the Reciprocating Pa1·ts Given.- It has been shown in the Appendix that, assuming the connecting-rod to be of intinite length, the following simple relation exists be­tween the four different weigh ts of the rec iprocating parts and the d is tances of the cylinders

L (A2 - .82) = l (C2 - D 2 }, • • (l9)

or, wt itten in a som e whab altered form

~( £ 2 - A 2) = ( D2 - C2) • (XXI.).

If it be the objec t to design an engine which is to be balanced by m aking the smalles t alterations of the weights of the reciprocating parts, it has to be ascertained, at fi rs t, whether the minimum weights A, B . C, and D, calcula ted from the drawings will fulfil equation (XXL). As this will not occur very often, some suitable alterations in the four weights have to be mad e. The wei~hts A, B, C, and D being, at firab. taken as light as posstble, the fulfilment of eq u1.ti0n (XXL) can oaly b 3 arrived a t by the increa3e of one or two of the weights. What alterations will be mo3t sui table can easily be sean from (XXL).

In order to give a simple example, let us put down the following values :

A = 6 ; B = 7 ; C = 8 ; D = 10; L = 10; l = 4;

L therefvre - = 2.5. l

These values in t roduced i nto equation (XXI.) will give on the left. ha.nd side 2.5 (49 -32), and on the right-hand side (100 - 64), or 32.5 and 36. If now, on the left be written 50.4 ins tead of 49, the equation will become correct, and con~equently it will only be n ecessary to increase the weight B from 7 to J50.4 = 7.1 to make the b!l.lance p ossible. To arrive at the balance in another way, i t is only necessary to increa3e C to ~67:5 = 8.22.

The crank angles which are requisit e for balan ce will result from the triangles as represented i n Fig. 7. Con ­sequently, it js only necessary to calculate the values

A L + l. B L ..1. '· A L - l . B L - l . 2' :t' 2' 2'

C L - l ; D L_ =- l ; C l ; D l , 2 2

and to dra w Fig. 7 to a definite scale. Then lines para llel t o the sides of the triangles are to be drawn through the point 0 (see Fig. 8). These will give the requisite arrangement of the cranks.

The method above d escribed can be usefully applied in cases where it is desirable to make a preliminary investi­gation as to whether the given minimum weights of the reciprocating parts will permit of a balance, and what alterations in the weights m ay be eventually necessary. A fter having decided upon a certain arrangement, ib is evident that the desi~n of the engine must be carried out in the usual way, takmg the valve gear into consideration. No doubt the reciprocating weights and the crank angles will be somewhat influenced by this.*

LAUNCHES AND TRIAL TRIPS. M E ns. ! &VINE' Shipbuilding and Dry D ocks Com­

pany, Limited, W est H artlepool, launched, on April 3, a finely modelled steel screw s teamer, built for the W est Hartlepool S team Navigation Company, Limited. he is of the following dimensions: L ength, 352ft.; breadth, 48 ft.; and depth, 27 ft. 9 in. ; and of a measurement cargo capacity of ?OOO tons.. Engines of the t~i~;>le-expan ­sion tvpe are bemg su pphed by 1\'Iessrs. '\V 1lham All an and Co., Limited, Sunderland, with cylinders 25 in. , 40 in., and 66 in. in diame ter, with a stroke of 45 in., st eam b eing supplied by two single-ended boilers, con­structed to work at a pressure of 160 lb. The vessel was named Boltonhall.

- - -The steel scre w s team Fir Osmo left the yard of her

builders, Messrs. Craig, T~ylor, and Co., Stockton ·on ­T ees, for her t rial t rip, on Thursday, the 5th inst. The dimensions of the vessel are 254 ft. by 37 ft. by 18 ft. moulded. The engines, which have been constructed by M essrs. MacColl and Pollock, Sunderland, have cylinders 18~ in., 30 in., and 49 in. in diameter by 33 in. stroke, with two boilers working at 160 lb. p ressure. An a verage speed of close up on 11 knots was obtained. T he owners of the vessel are the Bjorneborgs Angfar tygs Aktebolag Porin Hoyry lai Ya Osakey htio.

T he P eterel, torpedo-boat destroyer, built and engined at Pal mer 's hipbuilding \V orks, .J arrow, had a three

• * Our space will not permit us to reproduce the lengthy

Appendix by which H err cblick 's paper was accon:­pa.nied .

[ APRIL 20, I 900.

hours' consumption trial at P ..>rtdm )Uth on Friday the 6th in~t. \Vith a. mean indicated hor.ie·p 'J wer of '6276 a.nd 2. 9 in. of air pressure the speed for the three hours w~s 30.054, and the mean of six runs over the measured mtle ~ave a speed of 30. 097 kno~. The highest speed on the m1le was 32.59 kno~, with :378.9 revolutiont~. There wa..q an entire absence of vibration. The coal consump· tion worked out at 2. 3 lb. per unit of power per hour.

The screw steamer Briarda.le, recently launched from the shipbuilding yard of Messra. S hort Brothers, Sunder­land, to the order of Messrs. G. H. Elder and Co., of Newcastlo-on-T yne, went out on trial on the 7th inst. The vessel was taken a. series of runs over the measured mile, when a mean speed of 11! knots was attained. The vessel is of the following dimensions, viz : Length, 327 ft. ; b readth, 42ft. ; depth moulded, 26ft. 9 in. The machinery is by the North-E astern l\1arine Engineering Company, Limited, of Sunderland, having cylinders 23 in., 38 in., and 62 in. in diameter by 42 in. stroke, with two boilers 14 fb. 6 in. by 10 ft. 6 in., working at 160 lb. pressure.

The large screw s teamer Norfolk, built by the Sunder­land hipbuilding Company, Limited, to the order of Messr .s. Birt. P otter, and Hughes, Limited, of London, for their well-known line of Australian steamers, pro­ceeded to sea on her load~d t rial trip on the 7th inst. The length of the vessel is 420 ft. between perpendiculars: breadth, 54 ft. ; and d epth moulded, 32 ft. The main engines are on the tri-compound principle by the North­Easte rn M arine En~ine Engineering Company, Limited, Wallsend-on -Tyne having cylinderJ 30 in., 48 in., and 78 in. in diameter by 54 in. stroke, and fo l;r large boilers fitted with H o wden's forced dra ught. The runs over the measured mile at Whitby gave a mean speed of 12 knots. This vessel having b een chartered by the Government, was fitted by the builders right fore and aft on two decks, with stalls for 1100 mules, which she will carry from Gibraltar to S outh Africa, and also, in addition to these stalls, all necessary water service and accommodation for muleteers, &c. , has been fitted . This is the fifth vessP.l built by the Sunderland Shipbuilding Company which has recently been fitted up for Governmenb transport ser vice in connection with the present war, both for con­veyance of troop~, horses, and mules.

The steel screw steamer Dulcie, built by Messrs. Wil­liam G ray and Co., Limited, for ~~rs. C. Ni~ls~n and Sons, West H artlepJo], had her tr1al tnp on Apr1l o:. Her principal dimensions are: L~ngth . over all, 2;8!> ft. ; breadth, 41 ft. 6 in. ; depth, 20 fb. 2 m. The eng1nes are of the tri ple·exp Sl.osion type, m.anufactu:ed a.t t~e Cen~ral :Marine E ngine "vVorks, the cyhnde~ bsmg 2li tn . 34 l!l ·• and 57 in. in diameter, with a ptston stroke of 39 1n. There are two boilers working at a pressure ~f 160 lb. per square inch. The trial was in every way sattSfactory, the speed being 11 knots. --

The French Transatlantic Company ba.ve la.~ncbed t~e second of their new Atlantic liners-the Sa.vo1e. She 111

177 metres long, 18.30 metres beam, 12 metres ~eptb, and she will displace at 7. 75 metres, draught, 1:>,400 tons. The m aximum speed is to be 22 kn~ts, ~nd the m~an speed 20 knots. Th~ S~voie b~s twm . tnple.expa~~lOn engines, and 16 cyhndncal ?o1lers, wtth. 80 auxih~ry engines. The coal consumpt10n per day 1s expected to be 380 tons. The vessel has four complete decks, e~­cluding the promenade and sha.de deck, a.nd therh~rd13 accommodation for 440 firs t, 120 second, and 400 t 1 -

class passengers, the crew numbering 382 men.

The trials of the shallow-draught gunboats Argusd 0nd Vi ilante built by Messrs. J obn I . Thornycroft an o., of gChiswick, t o the order of the French . G:overnmedt. have been successfully completed. The .Vtgilante me. e her first run down the river on tb.e 9Gb ~nst., and ~~ an official trial of two hours' durat10n Wlth full lo~tU 00

board attarned a mean speed of 1~.25 ~nots. T~e Al~s satisfactorily completed her ~ffi01al trtal on Frta~ 13 4 the 6th inst when she attamed a mean spee o · , b , knots on a two ours run.

--1\II essrs. .J oseph L . Tbompson and Son~, Limited, un;

derland launched on the 3rd inst . the steel screw stea~e Eagle Point, built for the N<?rf~lk and N~r~hef::~~cf~ Steam Shipping Company, Ltml~dh. The 'fded depth of long and has a bea m of 51ft. w1t a mou A · 30ft~ 6 in. be i built for t,he ca.ttle and ~!leraJtted~~; can trade, the whole of the tw~en deoks . 1Dghave been the carriage of cattle. The en~m.es and boilers LimitE:d, constructed by l\l!essrs . .John J::?tckmson an;d Sons,e the dia-

underland and are of the tr.~l~-expan.s10n tydp .~ . by , 1' d b . 5 43 1D an .. , lD., meters of the cy m ers emg · 10· • .· ' kin at

48 in. s troke with three singlfie- endde~t~o~~~d~~fs for~ed -200 lb. pressure of steam, and tte Wl \

draught arrangement.

Messrs . .John Fullertoa and Co., Paisley, laun:ed ~s~ the 3rd inst . a steel screw s~eamer of at;ut ~~~ Gfor~e register, which has been bu1lt to the 0~v'!Je~ sla~ trade. Farren, Ca.rnar von, for ~he . N ortb wer are to be Com~ound en~ines of 600 mcltoa.ted hor;hUfield Work~, supphed by Messrs. Ross and Duncan, Go van.

Th ts of coal from Ger-G &RMAN CoAL E XPORT .- eexpor ared with

many last year were 13,043,17 4 tons. as co~p 1897 In 13,989,223 tons in 1898, and 12.~9,907 ton:0

1~r figured these totals the ex ports to Austria add 4~42 ~6~ tons re· for 5,134,866 tons, 5,466,125 i{n

1j· adn fo~ 3 G!)5 859 tons,

sp{)ctively; and tbo3e to o an , . i • 3,724,559 tons, and 3,557,285 tons respecttve y.

•

•

•

•

APRIL 20, I 900. J

"ENGINEERING" ILLUSTRATED PATENT RECORD.

COMPILED BY w. LLOYD WISE. ur.ROTED ABSTRACTS OF REOENT PUBLIBHED 8PEOIFICATION8

UNDER THE AOTS 1888-1888. 'l'ht number of v~1os given in the Specijicati01• Drawi'¥JS is stated

in e.a,ch case ; whMe '1l.01~ a-t·e mentumed, the Specification is not illustrated.

Where in'l16ntion8 are communicatedfr~m abroad, the Rames, ~c. , of the Communicators are given in itaUcs.

Copiu of Specijicati01l8 may be opta;i'n.ed at the Patent Otfi,ce Sale Branch, S6, South~mpton Bttildtngs, Chance?y-la7~, JV.C., at tJte uniform price of 8d.

i'ht da-te of the advertisem.ent of the acceptance OJ a complete Specijica.ti~n is, in each case, given after the abstract, unless the P~nt has been sealed, ·when the date of seali'n.g is given.

.-tny pm-son may at any time Wt"thin two months from the date of the adwrtisement of the acceptance of a c01nplete Speci/icati01l, gi'l16 notice at the Patent OJ]ice of oppositim to the grant of a Patent 01~ anv of the grott.rut:S me11~ in the .d et.

E LECTRI CAl, APPARATUS.

5657. G. Marconi, a n d The Wireless T el egraph and Signal Company. Lim ited. London. Wb·eless -rele~phy. [1 .tlig.] March 15, 1899.-According to this invention, which relates to apparatus such a.s is described in -specificat ion No. 12,039, of 1896, the aerial conductor is per· manently connected to one terminal of a sparking appliance ~eh as the secondary winding of a Ruhmkortf coil, the other terminal of which is connected to earth or o~ber large capacity, the accumulation of atmospheric electricity in the conductor being thus prevented. The signals, as in the apparatus de· scribed in the specification referred to, are sent by means of a

,., ______ ,

llorse key in a local battery circuit , through the primary wind· ing of the coil. The arm of the key is prolonged beyond its pivot, and carries an insulated terminal, which is permanently (lOnnected with ~he conductor through the coil, this arm beiog so arranged that immediately it is released by the operator it turns on its pivot and connects the receiver to the conductor. By these means the operator is protected from shocks due to atmospheric electricity, and it ie rendered impossible for him to accidentally operate his t ransmitter, thereby causing a spark wbioh might injure the imperfect contactt.,when the conductor is connected with his receiver. (.Accepted .DJ. arch 7, 1900.)

6349. Siemens Br others a nd Co., I.im ited. and G. W. P erry, London. Telegraph Posts. [4 Figs.) .March 23, 1899.-A P.?St for the support of a. telegraph win, or the like, is fitted Wlth a steadying plate, the underside of which is furnished with ridges, the lower edges of which are sharpened. For flxing the pos~ in soft ground, the plate is placed on the ~rface of the ground, and the lower end of the post ie passed through it and driven into the ground in the usual way. The post has a taper part, or a collar or shoulder ; and when it has been

F. , tg.J.

r=

'11/JJ>>n>

Fig.4.

•

'm»nn

•

~ .a.

"' \ I • /

I I

' • I I

•

~o far driven into the ground that its collar , shoulder, or taper part bears on the plate ; then, by further driving, the plate is ~ven with the post, consolidating the ground below, and form· mg a base· for the post. This mode of steadying a post is prefer­able to that in wbtch the steadying plate ie previously secured to the post ; as not only is it unnecessary to dig to some depth a bole as large 1\S the plate, but the ground is consolidated by the act of dr.h:Wg the ·poat, whereby it is held more securely in an ereot pos1t1on. (Accepted JJfarch 14, 1900.)

25,295. J. A. F lemtng, Lond on. Electrica l Resist· ance Measuring Inst ruments. [12 Figs.] December 20, 1899.-This invention has for object the construction of a Wheat­stone br.idge of the cc dial pattern box bridge " type, suitable for workshop use, and having no exposed ebonite or lacquered brass­w~rk excepting the terminals for m"ing connection respectively wttb the bat.tery, the galvanometer, and the resistance to be mea· ~ured, the liability of the ebonite to Jose its insulating qualities m consequence of exposure to dirt, and other objections to this t)•pe of bridge being thereby to a great extent obviated. The bottom and the cover of the box are removable, and the resist. ance coils, the insulated discs on which they are mounted, the ~1 ntaot blocks, and the battery, galvanometer, and line wires are a I connected to the underside of the lid. The resistance coils are ~ially constructed to dissipate the beat generated in them dun~g the passage of the current, and each of them comprises a bobbm made of two semi-cylindrical open-ended sectiOns secured

E N G I N E E R I N G. •

~gethe.r with insulation between them, and a leng~h of resistance wtre cotle~ on the bobbin with its ends secured to the semi-oylin­?racal secttons. Means are ~rovided for preventing dust getting mto th~ pl~g holes, consistmg of a shutter having apertures cor· ~espondmg m number to the holes, but normally held out of co· mmdence t herewith by a spring. The invention also relates to the arrangement of the coils on the ratio arm to the construction of plugs so as to a\'Oid the formation of sho~lders thereon, and t<l the general construction and arrangement of the instrument. (Accepted J[a,·ch 14, 1900.)

8497. C. Bartenstein, Berlln, Germany. Bulbs for Electric Incandescence Lamps. [2 Figs.] April 22, 1~9.-The surfaces of the glow lamp bulbs are formed wi th otrc~lar ~roovee arranged equatorially, or at right angles to the long.ttudmal a~es of the hulbs, and sufficiently close to each other to dtffuse t he hJlht emitted by the filament, and to cause the entire surface ?f the bulb to appear luminous. This arrangement of f!roove~ IS prefe~red t~ that in which they are formed in meridian lines, smce the hght IS thrown more in a downward direction, and

_.,....

. ....

• r /

/ ' · '\ ") . ./ '- ., . '\ . ......

~· \ ......... 7 \ •

•

I l )/ ·~ • t: •

• r · \ • !J ,. .

/ • ( •

~ \

•

) /

\ •

6"' ) j (

in consequence of the direction of tbA grooves crossing that of the filament, a symmetricalluminou~ effect is produced ; the grooves are, moreover, c1rranged in the direction in which the bulbs are revolved i~ the mould during manufacture. so that they may be mo!e readtly, smoothly, and evenly formed than meridian grooves wbtoh prevent the rotation of the bulb in the mould. The form of the bulb and the cross-section of the grooves are not limited to those shown on the drawing, but may be varied as desired. (.dccepted ..1Larclt14, 1900.)

GUNS AND EXPLOSIVES.

16,157. B . ~· Maxim, London. P r ojectiles for Ord· n a nce. [7 Figs.] August 8, 1899.- Tbis invention relates to projectiles such as are described in applicant's prior specification No. 28,093, of 1896, in which a flexible meta.Jlic disc having a peripheral rim or flange is provided at the base of the projectile for compressing an obturating ring or gas check when the pres· s~e of th~ powde~ acts upon the disc. According to this inven­tlo~ the dtsc and 1ts peripheral flange are formed in two parts wbtch are subsequently joined together; and it is stated that the liability of the base-piece to fra<Jture at ~he part adjacent to the bend, when subjected to gas pressure is thereby obviated. In practice, a stout ring of mild steel, adapted to fit around a shoulder fonned at the base of the projectile, has an annular channel or recess in its outer or rear face to receive the peripheral edge of

Fig.2

I

the base-piece, which is made of tough rolled steel, and the two, when fitted together, are permanently secured by means of hydraulic or other pressure. The outer face of the ring is curved to more or less conform to the shape of the adjacent portion of bhe base-piece, so that when the latter is deformed by gas pres· sure, it does not meet with sharp corners on the ring, which would tend to fracture it. The outer face of the r ing is enlarged, and the base of the projectile is recessed to receive the enlar~ed portion, so that the forward motion of the ring will not be tm· peded when the pressure of the gas acts upon it and the base· piece. A semi-plastic gas check, such as that referred to in No. 680, of 1890, and No. 28,093, of 1896, is situated between the inner face of the ring and the base of the projectile. (.dccepted .lJ arch 14, 1900.)

~662. A. Luck, Dartford, K en t . E x plosives . No· vember 22, 1898.-Io the manufacture of bal.fistlc explosives of the class which comprises cordite, ballistite, gelignite, and the like, and which have hitherto consisted of a combination of the nit ro-compounds of glycerine and of cellulose, certain other esters of cellulose, such a.s the acetate, butyrate, or benzoate, are wholly or partially substituted for the nitro-cellulose, compounds of a more stable character, and possessing other desirable properties, being thus obtained. The compounds of these esters with nitro· glycerine are said to be gelatinous; those with nitro-cellulose may be gelatinised by means of a solvent. Other ingredients, Auch a.s barium nitrate, or di-nitro-benzene, may in some instances be employed. The resulting product may be formed into cords, flakes, or cartridge::; ; a good sporting powder being produced from 75 parte cellulose nitrate, 25 parts cellulose acetate, made into ~rains, and treated with a hardening liquid. (.dccepted 1Larch 14, 1900. )

4020. F. Stubbs and L. Burrows, Sheflleld. Pro­ject iles. [8 F igs.] February 23, 1899.-In addition to the driving band of copper, or other ductile material, with which

. 1. .2 .

projectiles for rifled ordnance have heretofore been provided, they are furnished with a sealing banCI bearing a general resem­blance to the driving bands referred to, except tbat instead of b~ing secured to the projectile it is free to turn tbereon ; hence

533 i~ takes no put in impar~ing a rotary motion to the projectile, and, when once projections have been formed on it corresponding with the rifling, these projections are not g round thinner, allow· iog escape of gas, as the projectile is propelled towards the muzzle. This sealing band is secured in a circumferential groove on the proj ectile, which may be the same as that which holds the driving band; it is, however, not prevented from rotating on the projectile, as already stated. (.dccepted Mcvrch 14, 1900.)

HYDRAULIC MACHINERY.

6936. W. G. Kent, London. Liquid Meters. [3 Figs.] March 30, 1899.-Tbie invention relates liO water meters such as that described in applican~·s prior specification No. 21,793, of 189!, and in which liquid is admitted to and \vithdtawn from a cylinder by means of a elide valve. In such meters it sometimes happens when the flow is small that the piston and valve do not pe~form t heir full stroke, the fluid passage through tbe valve bet~g consequently unduly contracted. To obviate this defect a. spnng or equivalent device is provided, which tends to move the valve to its extreme position immediately it has passed the centre, and the spring which keeps the valve against its seat is preferably employed for this purpose. This may be effected in

I

• ' .,

{ttH)

I

'

\-

- /!i~ ·.J·P· -I . l

11 I I I . .,

' •· .J

I I I

• I I

- I • I - -r- 1 --· I ' . , I I I

I I . - -.. --- I • ~ 7 --I I I I I

-t I ' I -,.

~ . 1.

I I ' I .. ' .. 0

I I I I 0 ' ' I

~ ·r ' T ' .. .. -... ----·i .. ~.r I... --l. .-::, _

~ --I ~ . J r·

I t- • I I

I ·- -- . _;

......

various ways, the arrangement shown in the drawings being pre­fe!red. ~ccordi.ng thereto, the valve enga~res a.nd moves with a. ~hde bav1!lg at tts up~er and lower ends flanges which project mto slots 1n ~ tube wh10h _forms a guide f~r a block on ~be upper end of the ptston-rod. Thts block comes m contact w1th one of the flanges when the piston is near the end of its t~troke and thus moves the slide an? valv~, at the same time ~usil:!g a roller pressed by the sprmg wh10h keeps the valve agamst 1ts seat to tra':el. up a doubly inclined projection upon the back of the vdlve un~tl 1t reaches the apex of the projection, when the action of t he sprmg causes the valve to complete ita travel independently of the stroke of the piston. (.Accepted Mfl1·ch 7, 1900.)

MACHINE AND OTHE R TOOLS, SBAFTING, &c. 3351. G. T. Smith an~ W. Ga rdner, Gloucester.

Too~~ed G_ea~ing. f1. ~-1 February 15, 1899.-Tbe object of th1s mventton 1s to provtde s1mple means for driving two parts of a machine in opposite directions or at different speeds from a e~gle shaft, while it would not be an easy matter to find a ma­chme of any degree of complexity in which this object is not to a greater or lees extent attained ; means tor attaining this end are described, aod appear to be limited to the driving of concentric elements, such as a shaft and sleeve, both of which are driven fr_o~ a single. shaft ~t right angles to them by means of bevel pm10ns, as W1Jl readtly be understood from an inspection of the

(3351) •

drawing, without further description; the elements being driven in the same or in opposite directions according as the pinions on the driving shaft are on the same side or on OJ?posite sides of the centre of the driven parte. There is one clatm a.a follows : The improved toothed jlear driving mechanism comprising a driving shaft carrying two bevel wheels or pinions arranged either on the same side or on opposite sides of the centre of two concentric parts to be driven either in opposite directions or at different speeds, and each of which parts carries a bevel wheel or J?inion gearing respectively with one of the bevel wheels or pmions carried by the driving shaft, substantially as described and as shown in the accompanying drawings. (Accepted March 7, 1900.)

3710. J . T. Wicks, B irmin g ham. Machine for W orkin g I n dla-Rubb er. [3 Figs.] February 20, 1899.­This invention has reference to machines for mixing india-rubber and other materials, and for g rinding and re-manufacturing' waste rubber; and also to callenders for the manufacture of

rubber sh.eet. The machine ~ompris.es ~hree parallel rollers mounted m a frame, and provtded With tptercbangeable spur gears, by means of which they may be rotated either at dif­ferent speeds, for mixing and grinding operations, or at the same speed for the purpose of caUendering rubber sheet. According

•

•

534 to one arrangement, tw J of the rollers are arranged one above the other, at some distance apart , and the third roller is mounted in front, so a.s to engage equally with each of them, its bearings consisting of blocks sliding in grooves in the frame, and horizon­tally adjustable by means of screws ; other arrangements, in which the third roller engages the upper roller only of the pair, are diagrammatically illustrated. The r ollers ar~, as is s t a ted to be usual, hollow, and internally heated by steam ; and the pro­visional specification states that t heir faces may in some cases be fl uted or bear a design. It is claimed that by means of apparatu s arranged o.a above described, t he materials referred t o may be worked more effic iently and more economically than by the machines now commonly used, which comprise two rollers only. (~ocepted bfarch 7, 1900.)

MININ~ METALLURGY, AND METAL WORKING.

4025. D. B. Morlaon, HartlepooL Iron or Steel J'orgtnga. [5 Figs.] February 23, 1899.-For the purpose of obtaining forging a of uniform and reliable structure bars a re employed of such sections a.s will, when laid in a pile, form prac­tically regular channels tor the free circulation of the beating gases without the employment of the usual loose pieces. The sections of the bars are such as to secure uniform he.ating , and to cause portions of each bar in each layer to penetrate and embed

Pig. l . '

~~-:~1

~ "M ~I f'll .... lt'-\~ ~

.c::"li e-o

~I -;-=-' ~

~~ -~ .[ -~,

'" ~I

~ 1r"' ~I

~I ~

101 ~.

\ci" ..

t.g_. •

,;. lf:l

- .l - ,r _, ,r

.... :"\ , ~ ") ,

.r =====~ - .1; ,r:

:-\ .~ .r ~ ) , ,t:

"""\t .r \..

Pig .:J. . . 4 .

themselves in t he ba.rs of the adjoining layer, and so form an interlocked instead of a plain welded surface. Various sections are illustrat ed and described. The bars in adjacent layers are, according to this invention , at rig ht angles to each other ; the applicant has, however, discovered, since the date of t.pplica.tion, that t he bars may advantageously be laid so that the fibres a re all in the same direction ; tbia modificat ion being the subject of another application, No. 13,448, of 1899. (A ccep ted J( atrch 7, 1900.)

SJIIPS AND NAUTICAL APPLIANCES.

7365. C. J. Rtdsdale, Folkestone, Kent. Feather­ing Paddle-WheeL [2 F igs. ) Apr i17, 1899.-l'hia invention relates to apparatus applicable in various cases where it is re­quired to be able to carry bodies round an axis without a t the same time causing them to rotate about t heir own axes, as, for example, in feathering t he floats of paddle-wheels and in rope­making cordeliers . The invention is d escribed by way of example as applied to feather paddle-wheel ftoats. Eaob floa t is fixed to a shaft mounted freely in the paddle-wheel ; and at a suitable angle (for example, rather more t han a righ t angle) to each float

'

Fig. 2.

shaft there is rigidly attached one end of a telescopic connectiof? , whose other end is joined to a disc which rotates about an ax1s inclined to the paddle shaft at somewhat more than a r ight angle. This disc is rota.ted by means of gear ing from the paddle-wheel shaft, the arrangement being such that as t he P.addle-whe~l is rotated so also is the d isc, and thus t he telescop1c connectiOns , whilst ;eto.ining t he floats in approximately parallel planes, a re able to clear one another by t ravelling about &? imagi!lary pro­j ection of the axis of the disc. The floats may 1~ some 1nstanoes ad ranta.geoualy b e made of more than usual w1dth. (A ccepted .Mar ch 14, 1900.)

STEAM ENGINES, BOILERS, EVAPORATORS, &c. 7178. J . Cowan. BoUer Furnaces. [8 Figs: ] ~pril.5 ,

1899.- A combined fu rnace is p rovided, one . p~rt of wb1ch ~s smt· able for burninu megasa (cane refuse) o~ s1milar fuel, V.:h1le the other part is a8apted for bu rning c~al, ettber of ~hes~ bemg used a t will for beatin~ a bo:ler. Accordmg- to a modificatiOn~ t~e fur­n ~es are respectively adapted fo r the use of coal dust ::~.na au, and c Ja.l a J fuel. The application of the i1;1vention to a. water-t ube boiler of the " St irling, t ype is d eson bed b_y way of example. The coal-burning furnace is located a t .what IS usually t he fro~t end of a boiler of this t ype ; and accordmg to one arrangement 1t

• E N G I N E E R I N G. is furn ished wit h a sloping g rate fed by an elbow-shaped pasaage above it, and with a. removable aahpan beneat h the firebars, which also serves as a damper to abut oft communication with the other furnace. The fu rnace tor burning coal dust or megass is situatad at the rear end of t he boiler , and is also fed by an elbow·sha.ped passage above ; and it communicates with a combustion chamber, t h e roof of which slopes downward beyond the fire -bridg e, t he heating gases reaching the boiler t hroug h an opening near t he

fire-bridge of the coal-burning furnace. The lower boiler d rums rest on a floor, which forms the root of the combustion chamber ; and suitable a~ertures closed by doors afford access to the fu r ­naces , co~bust10n cbaml>er, and aahpita tor cleaning, a ir supply, and t he like. Where coal dust is u sed a.s fuel, it may be injected by any suitable and k nown apparatus into a furnace furnished with a. combustion chamber, generally resembling that above d escribed. (A ccepted 1J1 arch 1, 1900.)

1382. R. B. Ransford, London. (Soi!UU J . et A . N i clamse1 ~alris. ). BoUer Tubes. [3 Pigs.] J anuary 22, 1900. - This 1n vent10n has reference to t ubes especially suitable for Niclausse boilers , having formed thereon cones wh ich fit into corresponding seats in t he walls of t he header, such as those de­scr ibed in prior Spfcification 18,166 of 1898. According to t his

DD .2

in vention the tube is thickened a t ita end, and the outer cone is formed on this thickened por tion and not by expanding the tube, as in the specification referred to, and t he end of the tube is closed by a plug which screws into this t hickened por t ion, instead of by a cap screwing on to the outside of the end of the tube. (~ccepted il[ arch U, 1900.)

8274. D. N. Bertram and s. MUne, Edinburgh. Ejector. [3 Figs.] April 20, 1899.-Tbe interior of t he injector is more or less of the ordinary form, with the usual jet and ejector inlets and delivery ou t let ; but instead of a narrow spindle valve within a narrow jet nozzle, a double conical valve 1s em· ployed, acting agains t a wid er nozzle, and producing an annular mstead of a solid jet, t hereby affording a larger area of ex traction for the aarue volume of fluid. The valve may operate to produce and regulate the jet either by an upward or a downward move-

• • • ... . • ' ' • ' ' ~ .

F'1]. 1.

~-----, -----· • • • • • • • • •

Fi-g. 2.

ment; and t he opening t hrough which t he ex t raction takes place may be cont rolled by the adj ust ment of the valve, or of a part of the ejector casing adapted t o be moved to or from t he nozzle. Two alternative forms of apparatus are illustrated in Figs. 1 and 3 reape0t ively ; in the former t he val ve closes t he jet orifice by a downward, and in the latter by an upward, movement . Fig. 3 of the drawings is seemingly referred to as Fig . 2 in the latt er por tion of t he specification , and in t he th ird claim ; and while i t is s tated t hat three adjustments are prov ided io this construe-

•

[APRIL 20, I 900.

t ion, t wo appear to be specifically referred to. (Accepft d March 14, 1900.)

TEXTILE MACHINERY. ~7. D. McKellar, Perth. N.B. Beetltng Mach!De

[4 P'!{IS.) Mar~h ~4, 1899.-Tbis machine is desip1ed tor th; beethng and fimshmg of textile fabrics. I t compnses a row of beetles or hammers d riven by steam or compressed air which strike on ~metal roller or beetling beam abo,·e t hem, ove; which the cloth 1s conducted by me:.ns of rollers above the beam some of wh ich are heated by steam. The heads of the beetles 'which are made of alumin ium, are akewed relatively to the dire~tion of the cloth , to avoid t he formation of furrows thereon. The

{ )

tJ: 1- t ~

tJ: t= b:

;:::

IHI ~

•

-,.. ( ~

= L :: J

:::

A ,1-\A .11 A "'I A A A ~g) ..... ..... - .... ... .... .... .... .;:

./ \.. \ L r

beetles are rapidly vibrated by means of pistons working m cylinders, and acted on by steam or other fluid under pressure,. the working fluid being admitted to annul a.r recesses around the p istons, which uncover porta in the cylinders, automatically distributing the fluid , and dispensing with distributing valves. The rollers are rot ated from a fa.at-and-loose pulley by meaoe of gearing, comprising , in the example illustrated, a worm and worm wheel for the beetling roller , and a belt and pulley for the­rollers on which t he cloth is rolled. (.Accepted March H, 1900.)

VEHICLES. 7271. G. Daimler, CanllStatt, Germany. CooliDg­

Brakes. [2 F igs. ] April6, 1899.-The object of this invention is t 1 t ffec t the cooling of a vehicle brake while it is in operation ;. and for this purpose the mechanism by which t be brake is actuated is so connected with the tap of a water reserrolr that

(1m J

the tap is opened whenever the brake is put on, and closed when it is taken of. In t he example of apparatus illustrated, the br~kde consists of a disc to the edge of which brake-blocks are app~e by levers linked to a handle which a.lso op.erat~s the tap wbioh supplies t he cooling liquid . The 10vent10D 1s not, h~w~r), limited to this particular type of brake. (Accepted March 1

1 1 ·

9026. G. Daimler, Cannetatt, Germany. 'YarmlnJ Motor Vehicles. [1 F ig.] April29, 1899.-Tbe obJect: otet~ invention is to effec t t he warming of the body ~~ the cam ag e [a means of the waste beat of the motor. For tbl8 purpo~e .ther t pro,·id ed in t he fron t of the carriage ~ beater conslBtHJl 0 ~ aha.llow box containing a number of honzo~tal tubes lea tlDgtbe­an air accumulator, the front ends of wh1ch are open o

-----------------,

t

11~6 • t . . t . tained in the u1 enor

atmosphere. The ciroulatm~ wa. er 18 C?D th tubes which is of the box, and is cooled by the au entenng eto whence it is mE'anwbile heated on it~ way to t he a~cum~odv ~brougb a pipe conducted to other port1oos of the carnage r drau ht is m· furnished with a reg ulating valve. A strong atr be larriage is duced through t he cooling pipes by ahfa

1n, 80 tr.r:tetd (Acetpted.

not only heated, but also t horoug Y ven 1 ·

March 7, 1900. )

UNITED STATES PATENTS AND PATENT PRA~OE. . · f s patented ID the

Descriptions with illustra.t1ons of 1oveo 10n t time &Dd United States of America from 1~7 to tb\~~~tes, uUt.y be reports of t r ials of patent law cases !n ~he ~~ 15 and 36, Bedford· consulted, gratis, a.t the offices of E...'IOINRRR •

s treet, Stran~

•