THE WILLIAM SCOLNIKCOLLECTION OF

PRECISIONELECTROMECHANICAL

CLOCKS

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PAGE INDEX

2 RIEFLER ASTRONOMICAL CLOCK No. 147

4 ENGLISH SHORTT FREE PENDULUM CLOCK No 47

7 H. A. CAMPICHE ELECTRICALLY IMPULSED DISTRIBUTINGCHRONOMETER No. 2

8 RUSSIAN FEDCHENKO ASTRONOMICAL PRECISION CLOCK No. 10

10 EARLY SHORTT OBSERVATORY ELECTRIC REGULATOR

12 LEROY CONSTANT PRESSURE OBSERVATORY PRECISIONREGULATOR No. 1403

14 RUSSIAN “ETALON” SHORTT TYPE OBSERVATORY CLOCK No. 6

16 PRECISION TANK REGULATOR BY JOHN GODMAN

18 SELLIER PATENT DOUBLE PENDULUM HIGH PRECISION CLOCK

19 Biographical Information

S. Riefler No. 147- Munchen 1905

Below is a copy from the Riefler archives showing the entry for Riefler No. 147. The entry indicatesthat the housing is glass and Pendulum # 727 type J(1) was supplied with the clock.

RIEFLER ASTRONOMICAL CLOCK No. 147

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RIEFLER ASTRONOMICAL CLOCK No. 147From the beginning of the 20th Century, RieflerClocks were the de facto precision timekeepers usedin Astronomical Observatories as well as the centraltime service installations frequently used as thePrimary National Standard Timekeeper in manycountries. The stated precision for the Type D clockwas 10 milliseconds per day although better rateswere frequently achieved. Riefler made a total of779 recorded clock of every type by the timemanufacture ceased in 1965. Of this number fewerthan 15% were in glass cylinders and very few ofthem survived to this day. They ceased to supplyclocks in glass by 1915 and are extremely rare. ******Riefler Astronomical Precision Regulator #147 hasan interesting history and has only changed handstwice. It was originally acquired by the WestonElectrical Instrument Company directly fromClemens Riefler in 1907. The Weston ElectricalInstrument Company was founded in 1888 andbecame one of the larger firms making precisionelectrical instruments. By 1909 they were one of thelargest manufacturers in New Jersey and werelocated in Newark. When the clock was purchasedit was originally installed in a tenperature controlledchamber which was magnetically shielded. It wasused to transmit highly accurate seconds impulsesfor the control of the factory generator speed

(Above) A detail showing themicroscope for the adjustment of thependulum amplitude.

(Left) The original vacuum pump usedwith Riefler #147 to reduce the effectof barometric pressure and to makeadjustments to the rate.

used in the calibration andstandardization of frequency

meters. The clock was actually selected byProfessor A.F. Ganz of the Stevens InstutiteHoboken, NJ who was commissioned by Dr.Weston to visit Riefler directly. Since at that tine,it was the most accurate clock made, ProfessorGanz selected the type with electric drive and Invarpendulum with a stated rate of less than 30milliseconds per day.

I acquired this clock aproximately 32 years agoIt is in fine original condition with the original

pendulum and original vacuum pump. It iscomplete with the original stick barometer andoriginal thermometer. It is currently running andkeeps an excellent rate. According the the originalRiefler archive records, the pendulum suppliedwith the clock was type J(1) fitted with a weightpan, adjustment scale for the microscope andmicrometer bob height adjustment. At the time, nofiner or more accurate clock could be purchased.

The clock is complete with a copy of the Rieflersetup instructions and an original price list.

14” diameter, 55” high

(Left) A photograph of the RieflerType D from an early catalog..(Below) A Riefler Catalog from Ca.1915 showing the Type D onthe cover in a copper cylinder.

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The English Shorttt clocks were legendary for theirability to keep precision time. Up until the time theShortt-Synchronome clock was perfected, Rieflerclocks were considered to be the most accuratetimekeepers made.

The Shortt-Synchronome free pendulum clock wasa complex precision electromechanical pendulumclock invented in 1921 by British railway engineerWilliam Hamilton Shortt in collaboration withhorologist Frank Hope-Jones, and manufactured bythe Synchronome Co., Ltd. of London, UK. Theywere the most accurate pendulum clocks evercommercially produced, and became the higheststandard for timekeeping between the 1920s and the1940s when mechanical clocks were superseded byquartz time standards. They were used worldwide inastronomical observatories, naval observatories, inscientific research, and as a primary standard fornational time dissemination services. The Shortt wasthe first clock to be a more accurate timekeeper thanthe Earth itself; it was used in 1926 to detect tinyseasonal changes (nutation) in the Earth's rotationrate. Shortt clocks achieved accuracy of around asecond per year. About 100 were produced between1922 and 1956.

Shortt clocks kept time with two pendulums, a masterpendulum swinging in a vacuum tank and a slavependulum in a separate clock, which wassynchronized to the master by an electric circuit andelectromagnets. The slave pendulum was attached tothe timekeeping mechanisms of the clock, leavingthe master pendulum virtually free of externaldisturbances. (1)

Of the 100 Shortt Clocks produced by theSynchronome Company, 7 clocks were shipped toRussia for use in various scientific and astronomicalobservatories. Shortt No. 47 was shipped to the GaishObservatory probably in the late 1930’s.. I acquiredthis clock directly from the observatory in the late90’s and did minor restoration to bring it tooperationg condition. The clock is in excellentoriginal condition. Today original Shortt clocks arequite rare in operating condition and there are notmany in private hands.After WW2 began, it was no longer possible for theRussians to acquire English Shortt Clocks.

The clock is complete with a copy of the setupinstructions and a copy of the Synchronomecatalog describing the clock.

Free Pendulum: 9 1/2” diameter, 51” highSlave: 13 1/2” wude, 55” high. 9” deep

ENGLISH SHORTT FREE PENDULUM CLOCK No. 47

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ENGLISH SHORTT FREE PENDULUM CLOCK No. 47

(Far Left) The Type A slaveof the Shortt Clock. The maindial indicates the mean timeor sidereal time dependingupon the setup of the clockand the two smaller dialsbelow the main dial indicatethe free pendulum time andthe slave time. The Type Aslave contains the specialsynchronizer circuit whichkeeps the slave clock insynchronization with theFree Pendulum (Shown onthe right). The Type A clockalso contains theSynchronome seconds switchand also transmits secondsimpulses as well as halfminute impulses.

The Free Pendulumcontained in a vacuumchamber maintains itsmotion without anescapement in the traditionalsense. The pendulum isimpelled by the fall of thesynchronome switch and therelease of this arm is affectedby the slave clock kept inphase synchronism with it.This system of feedback isextremely clever.

The pendulum rod of theMaster Clock is made ofInvar and is provided with aweight tray for exactregulation. There is a beatscale at the bottom of thependulum which is observedthrough the glass bottom ofthe copper tank by means ofa mirror and microscope.

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ENGLISH SHORTT FREE PENDULUM CLOCK No. 47

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RARE H.A. CAMPICHE ELECTRICALLY IMPULSEDDISTRIBUTING CHRONOMETER No. 2

Patented in 1904 by H.A. Campiche, precisionelectric timekeepers of this type are rare for theperiod. The silvered dial is engraved DistributingElectric Chronometer No.2. The movement is offull plate construction in several tiers. The bluedbalance spring with terminal curve is of the helicaltype and the bimetallic compensated balance wheelis exceptionally large. There is a large solenoid coilthat is mounted between the plates which attracts apivoted armature when it is energized. The armatureoperates a system of levers to give impulse to thelarge balance through a brass piece attached to thebalance. Mounted on the end of the balance staff,a disc with a spring loaded palletgathers the teeth of a wheel which carries the secondshand and turns once a minute. This wheel also carriesa metal pin arranged to brush a pair of contacts atthe appropriate moment which energizes the coil.Another set of contacts can be used to operate a slavedial.

Campiche made a very small number ofchronometers of this type, probably fewer than 10.There are currently 3 that are known to exist all withserial numbers less than 8.

7 1/2” diameter, 10” highA copy of the 1904 Campiche Patent

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FEDCHENKO ASTRONOMICAL PRECISION CLOCK No 10

The Development of Fedchenko’s Clock

In 1948, Feodosii Mikhailovich Fedchenko, working in theTime Laboratory of the Kharkov State Institute of Measuresand Measuring Instruments started investigating methods ofmaking an isochronous pendulum. In order to obtainisochronous oscillations of a free pendulum, F.M. Fedchenkoin 1952 designed, built and developed an isochronoussuspension. At the Kharkov Institute during 1954, Fedchenkodesigned and built an astronomical pendulum clock of a newdesign, the AChF-1. In 1956, the investigation of AChF-1 andits improvements were transferred to the All Union ScientificResearch Institute of Physicotechnical and RadiotechnicalMeasurements.

The AChF-2 clock was built in 1952 and finally the lastdevelopment of the clock, the AChF-3 was built in 1958. It hasa precision in relative units of 2-3x10(-9) which was in therange of precision of quartz clocks. The clocks weremanufactured and tested at the Research Institute. (1)

The “secret” of the clock was in its special type of pendulumsuspension which F.M. Fedchenko designed and discoveredas a result of a serendipitous mistake in his experiments..

The Fedchenko clock was the last and most accurate clock ina line extending from Riefler, through Shortt and to the finaldevelopment in precision pendulum clocks, the Fedchenko.The Fedchenko was almost unknown outside of Russia. It wasDr. George Feinstein who, to the best of my knowledge,became aware of the existence of the Fedchenko clocksalthough there were none outside of Russia at the time.

(1) F.M. Fedchenko and his Pendulum Astronomical Clocksby Dr. G Feinstein. NAWCC Bulletin, April 1995

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12” diameter, 69” high

FEDCHENKO ASTRONOMICAL PRECISION CLOCK No 10

The Fedchenko Astronomical Precision Clockswere literally unknown outside of Russia.Sometime in 1996, I received a phone call from afriend Dr. Jerry Walker. He had a telephone callfrom a Russian contact offering him several

“clocks of high precision”, one of them being aFedchenko. He subsequently telephoned me andafter considerable negotiation, I managed topurchase the very first Fedchenko clock to cometo the United States. There was a great deal ofdifficulty in shipping the clock so I arranged tohave it driven through Poland to Germany wherea good friend took possession and had it shippedto me. When I received the clock, it was inexcellent condition with the exception of theunusual pendulum drive system. Fortunately, myengineering background enabled me to restore itto it’s original condition and now I had the firstoperating Fedchenko clock in the US. To myknowledge, it was the first of its type to leave theSoviet Union.

There were very few Fedchenko clocks made,probably fewer than 30. This clock came from aScientific Observatory in the Ukraine where it hadnot been used for many years. Fortuitously, it wasmounted in a secure room in the basement so itremained undamaged. There is speculation thatthe first dozen or so were produced under the directsupervision of Fedchenko himself.

The clock is complete with the astronomical slaveunit which is in itself unusual. The astro-dial is theonly Fedchenko slave I’ve seen with one, most slavedials having a more modern simple look.

There is also an original Fedchenko Clock manualwhich is signed in several places by Fedchenkohimself. And is entitled “Development andManufacture of Master Timekeeper for (OTTs)”.Themanual is bound, typewritten and signed. Withboard covers.

The clock has it’s original adjustable amplitudemicroscope as well as the original battery container(the clock was originally battery operated). Thebattery could run the clock for a number of years itoperated so efficiently.

In addition, It comes with a Wallace and TiernanPrecision Mercurial Manometer Type FA-173 sothat the vacuum in the clock tank can be adjustedvery accurately. The Manometer can be seenmounted to the right of the clock.

In 1999, Philip Woodward wrote a series of articlesin the BHI Horological Journal based upon datawhich I provided him from this clock. The articleswere later incorporated in a book of Woodward’sarticles on Time published by Bill Taylor and theBritish Horological Institute.

The very clever pendulum impulse mechanism. Youcan see the double wound coil and the exoticmaterial double magnets attached below thependulum bob.

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There are to my knowledge, only two examples ofthis type of Shortt Clock known, this one and one inthe Science Museum in London. I expect this is sobecause so few were actually made. In this example,the case is mahogany with a beveled glass door andtwin brass latches. The silvered regulator dial issigned Synchronome Electric in the seconds ring andLondon within the hour ring. The hands are bluedsteel. The Invar pendulum is suspended from amassive bracket with a substantial steel suspensionspring. The beat scale is of bone and fixed to a brassbar suspended by two vertical steel bars. There aretwo mahogany cased slave dials included with theclock both with regulator type dials and both signedas above. The dial movement in the clock is stampedwith the number 12. The construction of the dialmovements is straight line and quite unusual.

Starting around 1911, William Hamilton Shorttbegan a series of experiments in an attempt to makea very precise clock by impulsing the pendulum frombelow. He called this an Inertia Escapement andconducted his experiments in conjunction with theSynchronome Company. He published hisescapement in the British Horological Journal in1912. In this escapement, the pendulum was givenimpulse from below every second. TheSynchronome Company produced approximately 12of these clocks with Shortt’s Inertia Escapement butthey proved to be somewhat disappointing in thatthey never excelled the performance of the standardSynchronome clocks and no more weremanufactured. The clocks themselves are extremelyrare being of a more or less experimental nature(although, according to Hope-Jones, a dozen weremanufactured and tried on “responsible” jobs).

In the first editions of F. Hope-Jones book “ElectricClocks” he spends a good deal of time discussing theexperiments and testing of this first PrecisionRegulator by W.H.Shortt and it’s certainlyinteresting to note that in the following editions of

“Electric Clocks” this Shortt Inertia Clock is notmentioned. Hope-Jones himself, who some wouldconsider to be somewhat arrogant and officious,claims that “It must not be thought that this periodof experiment(with this escapement) and researchyielded only negative results. It produced one realachievement, the disassociation of the impelling andswitching function which introduced a time lag, notappreciated then, but destined to contribute to thesolution of the problem of the Free Pendulum” Bythis statement, Hope-Jones claims that he anticipatedthe development of the Shortt Free Pendulum.

SHORTT OBSERVATORY ELECTRIC REGULATOR

A drawing from theF. Hope-Jones book

“Electric Clocks”,First Editionshowing theoperation of theShortt InertiaEscapement

The regulator slavedial. There are two ofthese that are part of

the clock..

The straight linemovement used in theclock and also both of theslave clocks. It isimpuklsed by means of theelectromagnet at the top.It actually requires a verysmall amount of power toimpulse.

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SHORTT OBSERVATORY ELECTRIC REGULATOR

A closeup showing therelationship between the

impulse wheel which isattached to the bottom of the

pendulum rod and thethearm that drops on the wheel

as the pendulum passes.

A closeup of the ShorttInertia Escapement. Theiimpulse arm amd impulsewheel can be clearly seen.The two solenoids on theleft were used to reset theimpulse mechanism afterthe pendulum had passed.

A view of the clockshowing the

relationship of thependulum to the

Inertia Escapement.

As the pendulumpasses dead center asmall arm drops on

the freewheelingimpulse wheel.

This plaque is attached to the clock back board

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13” wide, 55” high, 7” deep

I acquired this clock 12 years ago but because Ilacked the necessary room to hang it, it remained init’s original, very large shipping crate until only lastweek. Had I known how absolutely unique andinteresting this Leroy clock was, I certainly wouldhave made room to install it and enjoy its uniqueand elegant mechanism. I sometimes reflect oncollecting and collectors and I’ve concluded that inmy case at least, anticipation is a very powerful partof acquiring something. I think in the case of thisclock, I carried anticipation a bit too far by waitingso long to actually see it and enjoy it!

This clock was originally commissioned by animportant American collector, the brother of JonnFoster Dulles (the US Secretary of State underPresident Eisenhower) on January 27, 1930 with adeposit of 10,000 Francs requesting a Pendule aPression Constante with a glass dome according tohis own sketch. The account was settled on August8, 1930 for a total price of 25,000 Francs. Theregulator was delivered almost a year later onDecember 2, the same year at the Morgan Bank inParis. The clock has only changed hands once sincepurchased having remained in the family until then.

.The firm of L. Leroy & Cie were specialists in theproduction of Constant Pressure Observatoryaccurate regulators, able to keep time with thehighest precision. The Paris Observatory was

RARE LEROY CONSTANT PRESSURE OBSERVATORYPRECISION REGULATOR No. 1403

“Pendule a pression constant”

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12” diameter, 58” high

RARE LEROY CONSTANT PRESSURE OBSERVATORYPRECISION REGULATOR No. 1403

“Pendule a pression constant”equipped with three clocks of this design mountedin the Catacombs beneath Paris at a depth of 26meters. Electrical impulses were sent to the ServiceL’Heure to provide precise time and to service thetime signals sent from the Eiffel Tower.

In order that the observatory clocks be as accurateas possible, they only show seconds, the reasonbeing that Leroy felt it was important to eliminatethe friction that adding the additional gears neededto drive the hour and minute hands produced.

The observatory clocks are also unusual since theybeat 61 times in 60 seconds. By doing this, it waspossible to set the clocks more accurately usingaudible time signals. This is a kind of vernier systemwhich was actually used for the first time byEarnshaw, enabling him to set the rate of hischronometers very quickly - something hiscompetitors were never able to do.

The clock movement has beautifully damascenedplates with a matte silver dial. The two dialobservation apertures show the remontoire action

and the ‘scape wheel. The clock uses a speciallyadapted Reid type escapement which acts on thependulum directly. The pendulum is Invar as is thependulum rod. There is a calibrated vernier belowthe pendulum bob to make adjustments. The clockis fitted with an exquisite thermometer/barometerwithin the tank. Adouble contact isactivated by thependulum and bothcircuits are closedmomentarily witheach oscillationexcept on the 61stswing when they arebypassed in order tomark the minute.

Supplied with the clock is the original voltagecontrol panel as well as the original largetemperature controlling thermometer. It is most

unusual to find original accessories of this type stillwith the clock. The clock is in excellent originalcondition, complete with the original amplitudemicroscope.

The special pallet arrangement ofthe Reid Escapement

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RUSSIAN “ETALON” SHORTT TYPE OBSERVATORYCLOCK No. 6

The history of the Etalon Factory Shortt typeobservatory clocks is an interesting one. Initially,the Russians imported several English Shortt clocksto be used in their scientific labratories andobservatories. After studying the Shortt FreePendulum system, they decided that they couldimprove upon the system and in 1934 at the All-Union Scientific Research Institute of Metrology(VNIIM) I.I. Kvarnberg with the participation ofProfessor N. Kh. Preipich started work on producingtheir own high precision pendulum astronomicalclock aimed at raising still furthur the precision oftimekeeping. Two years later, the

Etalon factory (in 1936) made and started testing thefirst models of the clock developed by Kvarnbergand Preipich with a free and synchronized workingpendulum. The Second World War however,prevented successful completion of the work whichwas then interrupted. Work on the clock wasresumed after the end of the war. At the end of theresearch in 1952 and the improvement of this clock,the diurnal variation of its movement - according tothe factory records was only 1 msec per day. Thiswould have amounted to about 1/3 of a second peryear which at the time for a pendulum clock wasquite

Tank containing the free pendulum The slave clock with synchronizing deviceused with the free penudlum

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RUSSIAN “ETALON” SHORTT TYPE OBSERVATORYCLOCK No. 6

amazing. The existence of the Russion “Etalon”Shortt style clocks was literally unknown outside ofRussia just as the Fedchenko clocks were alsovirtually unknown. I believe that the reason for thiswas that precision pendulum clocks were rapidlybeing supplanted by crystal clocks which were beingused as time standards and frequency standards herein the United States for many years by that time.Certainly in this respect, Russia was well behind therest of the world. The crystal clock was really notwell developed in Russia until 1948, many yearsafter their use in most modernized western countries.As a result of this, the interest in precision pendulumclocks, particularly outside of Russia, waned and asthe years past were completely supplanted by moreaccurate electronic standards.

well made. There is an unusual double doorarrangelment and all of the wiring is concealed undera false back as opposed to the English Shortt whichuses surface wiring on the backboard. From manypoints of view, the “Etalon” Shortt - even though itwas inspired by the English Shortt - is in manyrespects a better version. Being able to make the sideby side comparison shows this clearly.

I believe that this was the first Etalon Shortt clockto leave Russia.

Very few Etalon Shortt clocks were produced andthere is no one that seems to know exactly how many.I personally think that fewer than 30 or so were madeand that most were destroyed in the Second WorldWar. I only know of 4 Etalon Shortt clocks outsideof Russia, two here in the US, one in England andone in Germany. It’s possible that one or two othersare extant but they are exceedingly rare.

This one is Ne. 6 and was probably made under thedirect supervision of I.I. Kvarnberg. It’s in excellentoriginal condition and comparing the “Etalon” Shorttand the English Shortt side by side really makes aninteresting exercise. The Russian Etalon Shortt is farmore robust and has some interesting improvementswhich include jewelling in the free pendulummovement and a slightly different way of applyingimpulse to the free pendulum. The finish of themovements is better and the movements themselvesare heavier and sturdier than the English Shorttclocks. The large slave clock is most attractive andmade of fruitwood. It is quite heavy and exceedingly

(Above left) The slave clock movement beautifully finished(Above right) The dial movements in the door of No.6

(Above) The identification label which appearson both the free pendulum and inside the slave.

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Free Pendulum: 9” diameter, 51” highSlave: 14” wide, 55” high, 9” deep

UNUSUAL PRECISION TANK REGULATOR BY GODMAN

High precision regulator clocks that are designedto run in a vacuum are in themselves quite rarebecause of the additional cost and complicationsrequired in designing, making and maintaining anappropriate enclosure. For truly high precisionclocks, running in a vacuum has a number ofparticular advantages that contribute to thetimepiece’s ability to achieve its excellent rate. Oneof the primary and most obvious reason is that thevariations in atmospheric (barometric) pressure arecompletely alleviated and there are advantages withregard fluctuations in temperature also. In addition,rate can be carefully adjusted by changing theamount of pressure in the vessel containing the clockpermitting very fine rate adjustments.

This particular Precision Regulator was made byJohn S. Godman of St. Albans most likely in the late60’s or early 70’s while he was working for Mercers.It’s contained in a grey steel cylinder with a roundglass dome covering the dial and mechanism. Themovement itself is a variation of Riefler’s doublewheel escapement with his improvements in whichimpulse is given through the suspension spring.Riefler’s rementoire weight drive in which an armis lifted by an electric solenoid periodically resets arectangular weight which supplies power to the train.The brass bob pendulum has an invar pendulum rodand is a copy of the Riefler Type K Pendulum withmicrometer adjustment at the bottom.

There are very few clocks by John Godman knownto exist. I know of three others, one with standardGraham Dead Beat escapement and two withRiefler’s Escapement in wooden cases. The Rieflertype is in the British Museum in London. It is myunderstanding that this Precision Tank Regulatorwas used as the factory timepiece in the Mercerchronometer manufacturing facility for a number ofyears where John S. Godman worked for his entirecareer along with his brother Bill Godman. Itappears to be the only tank regulator he everproduced. And is in excellent condition.John S. Godman came from a long line ofclockmakers established in St Albans since

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11” Diameter, 55” high

UNUSUAL PRECISION TANK REGULATOR BY GODMANat least 1553. John S. Godman’s Grandfather was anorganist, tithe collector and maintained all of thechurch clocks in St. Albans. He was a good friendof Lord Grimthorpe. He made the Abbey Chimes forLord Grimthorpe and it is certain that he perfectedGrimthorpe’s three legged gravity escapement. Hedied in 1909 at age 79. His cousin, also named Johnworked for Thomas Mercer and when ThomasMercer died, Frank Mercer immediately took himinto his employ. In 1913, John was instrumental inmoving the Mercer factory to it’s new home. Hedesigned and built many of the machines used in themanufacture of various parts of the MercerChronometer and was known as a clever, ingeniousengineer

.

. .

John died during the war but had two greatnephews, John S. Godman and Bill Godman. JohnS. started his career at Mercers and later becomeresponsible for the machine shop. On retiring, heset up his own machine shop where he made anumber of very fine clocks including a chimingregulator with perpetual calendar and severalcopies of the Mercer-Cottingham ObservatoryRegulator. John S. Godman died in 1973.

Detail of astriking regulator

with perpetualcalendar made by

John S. Godmanin 1956. It is an

exceptional pieceof work

A detail of themovement

showing theswinging

suspension holderand pallet

arrangementThe Riefler style

double wheelescapement can

also be seen hereGodman

introduceda number of improvements in his version of the Rieflerescapement. One of the more interesting ones was his use ofaluminum to make the suspension holder and pallet arms. Bydoing this, he reduced the effects of inertia on the escapementconsiderably making the impulse to the spring more efficient..He also used knife edges and sapphire plates for the suspensionholder.

(left) Thesolenoid thatsets thewindingrementoire.

(right) Aview of the

double wheelescapement

*******

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SELLIER PATENT DOUBLE PENDULUM HIGHPRECISION CLOCK

In January, 1909 Pierre Sellier of Loriet, Francepatented an exceedingly interesting Constant ForceEscapement, Free Pendulum clock which utilizedtwo pendulums on a single movement, It appearsthat only one example was built as attempts tomanufacture it failed. This is the only example of theclock that is known. The French Patent No. 398809is listed under the heading “Precision Instruments,

Electricity, Clocks”.

According to HenryBelmont(1) in a letterdated October 1972,

“I think that this is asingle experimentalmodel, constructed bya French inventor,who has attempted,without success, tointerest an AmericanManufacturer. - Theidea was veryinteresting because itconsisted of making avery high precisionclock by the

association of a relatively free regulator pendulumand a “slave “ clock mechanism which operates thehands. The principle implemented is similar to theShortt-Synchronome astronomical clock”.

The operation is very interesting. The largetrapezoidal bob in the rear of the clock is actually thefree pendulum. A small hardened steel pieceprotrudes from the pendulum rod at the point ofsuspension. The compound bob which is just behindthe dial, is electromagnetically impulsed andregulated by the freependulum itself. As thecompound pendulumoscillates, it drops a smallweight on the armprotruding from the freependulum giving itimpulse once per second.It’s an extremely cleverarrangement.

(Above) A rather poor photocopy copy of a page from theoriginal patent document clearly showing this clock.

(1)Henry Belmont, letter on YEMA stationary dated10/18/1972. Henry Belmont is the holder of most of thepatents used in the entire world under the designation

“ATO License”

, 9” diameter, 24” high18

A little additional information about Bill Scolnik and the collection

For almost all of my adult life, I’ve had an abiding interest in time.I really can’t say why that’s the case but I realize now at 74, thatmost of the things I’ve done over my lifetime led in one direction.My interest in things related to time and timekeeping, precisiontime in particular, took me along an interesting and at times arewarding path. After graduating as an Electrical Engineer, Iworked at that profession quite successfully for a few years, but itwasn’t completely satisfying. In the early 60’s I started a businessrestoring and dealing in mechanical musical instruments whicheventually lead to repairing, restoring, buying and selling ratherinteresting timepieces and automata. One day while visiting a dealer

friend of mine, I noticed in his basement a rather unusual clock. I made an offer for itand it was eventually mine. The clock was a fine 18th Century organ clock made by PierrreJacquet-Droz. I spent several months restoring the clock and advertised it for sale. Oneevening I received a telephone call from Seth Atwood. He had seen my advertisementand had recently become interested in clocks. He eventually purchased this clock andvisited me in New Jersey. He told me that it was his first clock purchase and he appearedto be extremely pleased when he saw the clock. Seth eventually went on to create theTime Museum, one of the great clock museums in the world which has since beendispersed. Years went by and in the late 60’s I became interested in pocket watches. Iapprenticed to a well trained Russian watchmaker for many years and became a restorer,dealer and expert in complicated pocket watches.

During my frequent horological travels in Europe during that period, I had the opportunityto visit many museums in England and on the Continent. I became aware of an unusualclass of clocks that were amazingly interesting to me and were directed to one end –precision timekeeping. They appealed to me from many points of view. They wereinvariably mechanically interesting and they combined mechanics with electricity tocreate precision time and the creators and inventors of these clocks were scientists in thetrue sense of the word.

I started collecting precision electromechanical timepieces more than 40 years ago. Asthe years passed, I refined my collection to what I thought were the best and mostinteresting of these clocks. Because of the esoteric nature of precision time, by moststandards, few of these clocks were produced. I expect that because they were not

“decorative” in appearance, and as they fell into disuse and as better standards wereproduced, they were not preserved. As a result of this, very few really important precisionelectromechanical clocks survived. The fact that clocks of this type were produced forOnly 50 years or so also added to the few surviving number. I’ve had a great deal ofpleasure and excitement over the years pursuing these clocks, understanding them andworking on them. It has been a great part of my life and I would have to say most satisfying.

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