Remarks on the Type.Setting Machine. 287

wearied! His remarks corroborate the opinion that forcing pumps were thea littlo known in England. [See Ewbank 's Hydraulics, pages 295, 296.]

5 . . / t ~2ew kind of bread made in the form of wafers, and very cheap, With a screw press worked by a pinion and cog-wheel, for stamping, or forming, the wafers.

6. A mode of banking earih against the sea, or repairing breaches in canals, &c., with "artificial stones."

7. Water-prooJ garments~ light and proof against a continual rain, probably aa application of a solution of india rubber, or other gum. Caoutchouc was, however, then but little known, and according to some authors not at all.

8. , J l newe conceit in Peter IJZorks."~A device by which half the fuel expended in manufacturing salt-petre could be saved. He offered it to "the peter men" if they would give him one-third of the amount it saved them, but it seems without effect; perhaps an appli- cation of his wooden boiler.

The foregoing articles are the whole that appeared to have suf- ficient interest to be worth noticing. T . E .

F O R T H E J O U R ~ A ~ OF THE ~ A N K L I ~ I N S T I T U T E °

Remarks on the T~/pe-Setting Machine.

SIR,--I perceive in the April number of your Journal, (vol. vii, 3d series, p. 284,) an article giving a description of a type-setting machine, copied fi'om the Transaclirms of the Society o fd r t s , which seems to me to speak more favorably of it than it deserves.

The last paragraph reads thus : - - "When in full work, as many as 8000 letters, etc., have been set up by this machine in an hour; whereas, by the ordinary method, a good compositor can, on the average, set up about 1700 letters in the same time ; the wages paid in each case beiLlg nearly the same amount ."

From reading the foregoiug it would seem that the utmost power of the machine was the setting of 8000 letters in an hour; and this number I find, by actual measurement, to be equivalent to 3670 m's, and 1700 (the amount set by a compositor in an hour,) to 780 m's. 3670 m's are 550 more thau four compositors could set in the same time, but the distributing and correcting of the types are allowed for in calculating the amount set by a compositor, which is evidently not done on the part of the machine. It is estimated that one hand will distribute about 4000 m's in tile same time that he sets 1000, and if so the machine will require one hand to distribute. Each letter must, in themeant ime, be set out of the case, and put in the place appro- priated tO it in the machizm, which witl require at least three hands, making due calculation tbr their not having to stop to read copy~ these, with the two hands required to work at the machine, make six, as the nll/nber required to keep the machine in action. Six hands working at case .will set 4680 m's in an hour, which is a little over 1000 more than the machine will do in the same time.

~88 Mechanics, _Physics, and Chemistry.

The machine besides setting 1000 m's fewer in an hour than six compositors, will cost a considerable sum, and the price of the appar- atus, its wear, and its great liability to get out of order, are not taken into the account, which certainly should have been done.

Cincinnati, October, 1844. T . L .

] '011 T I I E f f 0 U R N X L OF T H E ~ R A I q K L I ~ I I ~ S T I T U T E .

Screens for Carding Engines. By page 102 of the February number of the Journal of the Frank-

lin Institute, I observe that letters patent of the United States, have issued to Joseph Munroe, of Hampden county, Massachusetts, for "the application to carding machines of a screen which will permit the dirt, motes, ~c., to escape without the cotton and wool, as des- cribed."

The screen referred to, is, beyond doubt, a very useful appendage to a carding engine, and though it may have been original with Mr. Munroe, it may not be uninteresting to the public to know, that this identical contrivance has been in use at the Rockland Cotton Mills, on the Brandywine, near Wilmington, Delaware, ever since the year 1828, and, though it was not original with us, we can bear testimony to its great utility.

Rockland, Delaware. W. WALLACE You~o.

Process for Preparing the Purple Powder of Cassius. M. Figuier gives the following as a certain process for preparing

the above named compound :--dissolve 800 grains of gold in five times their weight of aqua regia, prepared from four parts of hydro- chloric acid, and one part of nitric acid ; evaporate the solution almost to dryness; this evaporation is requisite to get rid of the acid. The chloride of gold beitJg redissolved in water and filtered, the solution is to be diluted till it measures 26 ounces ; fragments of granulated tin are then to be put into it, which becomes turbid and brown in a ~ few minutes; its tint gradually becomes deeper, and at the end of a quarter of an hour it assumes a fine purple color, the precipitate is deposited, and it remains only to collect it on a filter.

It sometimes happens, and especially when large quantities are operated on, that tbe precipitate does not separate, but remains in the liquid, to which it gives a deep purple color ; in this case it is merely requisite to heat the liquid slightly, and to add a little common salt; the product then immediately separates.

When the liquid holding the purple powder in suspension is de- canted to separate the excess of metallic tin, care must be taken that no particles of tin, which remain at the bottom of the vessel in the 8rate of a black powder, are poured off with it ; it is proper to allow the liquor to settle for some time, and afterwards to decant it ; this

ration should be repeated three or four times.--,/ /nn, de Ch. et de 8., Juillet, 1844. Load. Edin. and Dublin Phil. Mag.