bably took it from Porta's Natural Magic. He here mentions an inferior window glass then made in England.

41. Speaking by Signs "to be practiced by such as doo naturally lacke their speech."-Substantially the same as now practised in deaf and dumb institutions. Signs for the letters of the alphabet were to be devised, "but the vowels for the more readinesse thus.-A, upon the tip of your thumb on the left hand; E, upon the tip of your fore finger on the same hand, and so of the rest, so as when you lay the index, or forefinger of your right hand on the tip of the thumb on the left hand; the partie may note the same for an A." He had seen a lady and gentleman converse in this way in a company.

48. Candles and Lamps.-The price of tallow was high at the time Platte wrought, hence he advises the poor to make candles by dipping wick made of oakum in rosin, and to use them in the chimney place. He mentions floating lights for bed-rooms, and recommends lamps as far preferable for all purposes to candles. One special advantage was that rats and mice could not convey them into their nests, and set fire to the mats, as they often did with candles!

91. Oiled Paper in windows in the sixteenth century—Thin parchment to be stretched and oiled, by which its translucency was increased. This he recommends in place of oiled paper, because it would not, like the latter, be destroyed by stormy weather; and he thinks it might be used instead of glass in such rooms as are "subject to overseers,-i. e. to persons peeping through the windows. Landscapes might be painted on it "to make a pretty shewe in your windowes."

99. Projection. In this article he exposes the tricks by which itinerant jugglers, under the name of alchemists, deluded the unwary. He mentions a German artist over-reaching some young and rich merchants in a very clever manner. As they were on the qui vive, he lulled their suspicions completely by proposing that they should make the experiment, and find any thing while he would touch nothing. They, therefore, provided a crucible, coals and the quicksilver, (to be turned into gold.) The fire was kindled, one of them played the crucible under the nose of a bellows, as the juggler directed, another put in the mercury. When the contents were warmed, one of them was directed to give some gentle puffs with the bellows, as if to drive off the scoriæ, or oxide, from the surface of the metal. Then the cheat handed a small paper containing only a single grain of the magic powder which was to work the change. In half an hour the crucible was removed, its contents allowed to cool, and an ounce of pure gold was found in the bottom, being the weight of the quicksilver put in!

In this instance the cheat had previously conveyed the gold disguised as an impalpable power, into the nozzle of the bellows! The mercury in the process was evaporated, and hence the result. Platte advises every one "besotted with this art," to look out for false bottoms in crucibles, hollow iron rods, by which the varlets stirred the metal, fluxes in the form of powders, and false backs to chimneys, or such as had a loose brick closely jointed, that might be removed by

a confederate in the next room, and who, on a signal, ["as a hemme (!) or such like watchworde,"] given by the cheat while diverting the attention of the novice with a walk across the room, "and with the volubilitie of toung," may remove and convey some gold, or silver, into the melting pot!

51. Heating by Hot Water-To Dry Gunpowder.-Double vessels of lead, pewter, brass, or copper. The powder to be placed in the upper one, and the lower kept supplied with hot water.

50. Cement for broken Glass.-One part of virgin wax, and two of mastic, or fish glew beat till it becomes clear, dissolved in alcohol. This was used by a Dutch jeweller in cementing two of the queen's crystal cups that were broken; others used isinglass dissolved in Rhenish wine.

92. A strong Mortar for building, by mixing waste soap ashes with loam and sand, with a little lime. Some builders used it without lime.

98. The art of Memory.-Much the same as now taught. It was taught "by Master Dickson, the Scot, of late yeres in England."

101. A Portable Wagon moved by men within it for the use of soldiers. Nothing particular.

102. A delicate Stove to sweat in.-The portable vapor bath of modern days. Sweet herbs were placed in a caldron, and the vapor conveyed by a leaden tube into the bathing tub, where it issued through openings in a false bottom.

103. Refining Sugar.-Except the vacuum pan, precisely as now practiced. The white of eggs to clarify the syrup. Clay put on the moulds, &c., "tempered like pappe with water," &c.

Tempering Tools. In the SECOND PART, which treats of husbandry, he speaks of the value of salt in improving lands, and observes "some kinds of salt doe so harden yron, and doe give such temper to the edges of weapons, as that one may cut yron with them as if it were a piece of wood."

Boring the Earth.-To find marl by which to enrich the soil, he says, "I think it necessarie that everie man shoulde have a long augur, or percer, with several large bitts which he may put on and take off at pleasure, and with these he may search at what depth he will, alwaies marking what several veins of earth he fyndeth in the bitt of the augur."

The THIRD PART relates to distillation. He mentions siphons under the name of "crooked pipes," but there is nothing particular worth extracting, unless it were processes for making ypocras, and other old drinks!

Platte has none of those ridiculous recipes which disgrace old works, such, for example, as Cardan has given; one of which was to distil an illuminating liquid from the tails of glow worms! The whole is of a useful and practical character. In the part relating to moulding and casting there is nothing particular; flasks and moulds of plaster of paris, sulphur, and wax are mentioned.

The author winds up his book by "an offer of certain newe inventions which he will be readie to disclose upon reasonable considera

tions, to such as shall be willing to entertain them, or to procure some privilege for them. They are eight in number, but like Worcester's, not fully described."

1. "A newe kind of Fire."—He means a new fuel; from the cut representing it, and his description, it was what has frequently been since proposed, viz., a mixture of fine, or refuse, coal and clay worked up into balls of two or three inches in diameter. He says nothing of the materials, as a matter of course, but confines his remarks to the advantages of adopting it. It was "cheaper than sea-cole, sweeter in burning, and more regular shaped, being made in the form of balles." It was more durable; gave out no smoke; will employ thousands of poor persons to make it; will rather promote than hinder the coal trade; the materials abundant; will preserve timber for ships by superseding the use of wood for fuel; will reduce the price of fire wood and charcoal; and lastly, if introduced, ten per cent. of the profit may be given to the poor, and to maimed soldiers, &c.

2. "A vessell of wood to brew, or boile, in."-He means the old wooden boiler with a cylindrical fire place of sheet iron, or copper, in the middle. If so he was not the inventor, since it was described by Gesner forty or fifty years before, and is found figured in most works on chemistry of the sixteenth century.* It might, however, have been little known in England, or he may have devised a modification of it; of its value he appeals to the proofs in his "Apologie, published Anno, 1593; and if there bee anie person that, notwithstanding my testimonies therein produced, either perversely holds the same to bee impossible, or maliciouslie and slanderouslie reproove the invention of untruth; let him wage such a competent sum of monie as may counturaile (compensate) the discoverie of the secrets, and the author will make a public shewe thereof." He named it an artificial Salamander. It was cheaper than copper vessels-one would last twenty years-would save half the fuel usually consumed with others, and could easily be repaired by their owners.

3. "A boulting hutch."-A portable grist-mill turned by hand. A figure of this is given, but the interior is not exposed. It has six good qualities: its price moderate-it avoideth waste of meal and flour-saves bolters, which are costly-prevents uncleanliness in bolting. The objections made against it by the London bakers were false and malicious. It is durable, and will not be chargeable for repairs.

4. "A portable pumpe."-A figure of this is also given, but the construction is wholly concealed. It is a forcing pump, and a man works it without a lever. It is recommended as cheaper than any pump the author is acquainted with-light and easily transported from place to place by one man-will deliver from four to six tons of water an hour; placed in a tub it can be used for draining fens, or forcing the Thames water into kitchens; and it is recommended to seamen as a good ship pump. There is one feature in the description which renders the rest very doubtful. He says a man may work it five or six hours without intermission, and cannot possibly be

* 1 have seen it figured in a German work on Distillation, published in 1527.

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

5. A new 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 earth against the sea, or repairing breaches in canals, &c., with "artificial stones."

7. Water-proof garments, light and proof against a continual rain, probably an 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. "A newe conceit in Peter Works."—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 application of his wooden boiler.

The foregoing articles are the whole that appeared to have sufficient interest to be worth noticing.

T. E.

FOR THE JOURNAL OF THE FRANKLIN INSTITUTE.

Remarks on the Type-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 from the Transactions of the Society of Arts, 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 being nearly the same amount."

Fro.n reading the foregoing 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 than 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 the same time that he sets 1000, and if so the machine will require one hand to distribute. Each letter must, in the meantime, be set out of the case, and put in the place appropriated to it in the machine, which will require at least three hands, making due calculation for their not having to stop to read copy, these, with the two hands required to work at the machine, make six, as the number 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.

The machine besides setting 1000 m's fewer in an hour than six compositors, will cost a considerable sum, and the price of the apparatus, 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.

FOR THE JOURNAL OF THE FRANKLIN INSTITUTE.

Screens for Carding Engines.

By page 102 of the February number of the Journal of the Franklin 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 described."

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 Young.

Process for Preparing the Purple Powder of Cassius.

M. Figuier gives the following as a certain process for preparing the above named compound:-dissolve 300 grains of gold in five times their weight of aqua regia, prepared from four parts of hydrochloric 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 being 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 the 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 decanted 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 state 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 operation should be repeated three or four times.-Ann. de Ch. et de Phys., Juillet, 1844. Lond. Edin. and Dublin Phil. Mag.