From perfect solidity to the greatest degree of fluidity of which the alloy was capable, required, in the case of the first alloy given above, about 70° of temperature: and between the temperature at which a solid could pierce the alloy, and the stationary tem perature, was 8°. When the quantity of lead was doubled, the first interval was nearly 130°; and the interval between the temperatures of solidity and that at which the alloy could be penetrated easily, was about 20

:

These facts show, that in using fusible alloys, those should be preferred which contain the smallest quantities of lead a similar reason would lead to the preference of those cortaining the smallest proportions of bismuth.

*Tin is nearly liquid at the stationary temperature; hardens by plates or small masses, and becomes entirely solid at this same température.

Experiments were made to ascertain what quantity of bismuth could be added to tin without destroying the property just described. To one hundred parts by weight, of tin, one part, five parts and ten parts of bismuth, respectively, were added. The first alloy melted at 4394°, and had the general characters of tin in hardening; the second melted at 428°,

Stationary.

and had these characters impaired; the third had no stationary temperature above 400°, and lost its fluidity by slow degrees.

As it was thus shown that alloys of tin and bismuth presented no peculiar advantages, the alloys for temperatures below 355° Fah. were sought by combining the least quantity of bismuth which would give any requisite temperature with one of the alloys of the table on p. 104. For this purpose the alloy of equal parts of tin and lead was selected. as having appropriate characters in its solidification, and melting at nearly as low a temperature as any of the others in the table. It does not, of course, follow, that this allow when.com. bined with a given quantity of bismuth, will produce as low a fusing point as some other would; a question which, if it were worth deciding, experiment would determine. A few trials on this head were made by the Committee.

The following table gives the proportions of bismuth, which, added to an alloy of eight parts of tin and eight of lead, will give the temperature of the stationary points of an immersed thermometer between 355° and 326°. With the alloy which terminates this table the stationary temperature near the fusing point disappears, and another form of table is required for description.

All these alloys are liquid with solid portions, when the thermometer becomes stationary.

*Slow, not stationary.

nothing as definite as the stationary temperature, they are, of course, only approximate. A few trials made on the withdrawal of a metallic stem from the alloy, showed that the temperature at which this ceased to be possible was, for the alloys in the following table, between the temperature at which the metal lost its fluidity, and that at which it could not be penetrated by moderate pressure.

The fusing points of the metals used in the foregoing alloys were, of the tin, 442° Fah., of the bismuth, 506°, of the lead, 612o.

VI. To repeat the experiments of Klaproth, relating to the conversion of water into steam, by highly heated metal.

It being now well understood that an increase of temperature in a metallic surface may diminish the amount of vaporisation of a fluid placed upon it, the object of the following experiments was to study the phenomena attending the vaporisation of water by iron and copper, under different circum

stances.

* Stationary at 2050.

Stem drew out at 25°.
Stem drew out at 235o.

5 4 296 280 270 264 6.2 294A 269 2614 246 7.0 288 257 252 238 7.6 283 253 2428 234 232 226

8.0 272 246

1st. To ascertain the temperature at which a given small quantity of water will be vaporised in the least time, by copper, with different states of surface.

2d. To ascertain the same point for iron, in similar circumstances.

3d. To extend these deductions to the effect of introducing different quantities of water into copper or iron vessels, varying in thickness, in character of surface and heated by different sources, to various temperatures.

A number of bowls, of these different metals, of as nearly the same figure as could be obtained, and of different thicknesses, were

+ Stem drew out at 264°. Stem drew out at 2459.

provided. The bowls were portions of spheres, of nearly three inches radius, and were eight in number, three being of copper and five of iron; four of these latter were of wrought, and one of cast-iron. For applying heat to the bowls. a cylindrical vessel containing oil, and another containing tin, were provided; the former was about nine inches in diameter and four high, and the latter six and a half inches in diameter and four high. These vessels were heated by Mitchell's* alcohol lamp, or in the very high temperatures, by a charcoal furnace. The bowls were furnished with handles, which projecting, overlapped the edges of the cylinders, serving as baths for the oil and tin, and were thus kept in place.

The thermometers used in the experiments were carefully compared at the boiling point of water, and melting point of pure tin.

The experiments first to be detailed refer to the vaporisation of drops of water in copper

bowls of different states of surface, from the smooth polish to the roughness of oxidation.

Vaporisation of Drops of Water by
Copper.

1. The bowl, No. VII., of copper, sevenhundredths of an inch thick, was polished, but not very highly, and then placed in the tin bath while fluid; the tin, on solidifying, kept the bowl in its place. The thermometer was placed in a small cylinder of thin sheetiron, containing mercury, the cylinder being as near the cup as possible. As the experiments progressed, the surface of the bowl became, of course, more and more tarnished; and after the two series of results recorded below were obtained, a third showed a marked effect from the oxidation, by the increased vaporisation. One hundred and twenty drops, nearly, from the tube used, made up oneeighth of a fluid ounce; the weight of one drop was, therefore, about 47 of a grain.

124

NICKOLL'S PATENT CONDENSING RAILWAY LOCOMOTIVE.

Sir, I beg to invite the opinions of your correspondents upon the following proposed improvements upon my plan (Mechanics' Magazine, No. 653), for a railway condensing locomotive.

The boiler being constructed and situated as before described and represented, I would substitute in the place of the two equi-angular cranked condensing engines, D, two double-acting highpressure engines, with the addition of a condensing apparatus (consisting merely of an enlarged air-pump), which I would fix in the place of the condenser F; the apparatus in question, together with the hot water-pump, to be worked through the medium of a cross-head and separate cranked shaft, by an excentric from the shaft of the engines.

Concerning the refrigerator for cooling the hot water of the condenser, late experiments have convinced me, that to

maintain the cooled water, even at the temperature 80° Fah., an evaporating superficies of full 200 feet per horse-power would generally be desirable.

It is not necessary to employ the draft of a furnace, or other means, to produce: a current of fresh air in the refrigerator for moisture, so far from loading the air with its weight, communicates, like heat, increased expansion and elasticity; con-sequently, as by reason of the heat and vaporisation of the hot water in the res frigerator, the specific gravity of the air therein would be lessened, so by a little elevation of the eduction air-chambers T, the refrigerator would establish a current of fresh air for itself.

With a given quantity of steam, I anticipate about one-twelfth greater effect by the employment of my high-pressure condensing, instead of the ordinary highpressure locomotive; but the steam blast being wanting in the condensing locomotive, the expenditure of fuel might perhaps exceed in a sixth ratio what might be required in an uncondensing locomotive; the ultimate economy, how ever, (to pass by other well-known inconveniences of the steam blast,) I ap prehend to be more than questionable, because of the powerfully exfoliating influence of the very intense heat which the blast occasions upon the thin and oxygenisable material of which locomotive boilers are, and, with our present knowledge of metallurgy, must be constructed. Yet, if in no other point of view, assuredly as respects economy in the item of water, the superiority of my condensing, as compared with the ordinary locomotive, may be admitted-first, on the ground of the presumed somewhat more economical application of the steam; secondly, from the cooling influence of successive currents of fresh air upon the hot water of the refrigerator; and thirdly, from the vaporisation of a given weight of water, say of the temperature 100° Fah., (according to what one may infer from lately published experiments of Desormes), absorbing about one-third more caloric, than steam evolved of four atmospheres elasticity.

I am, Sir,

Your obedient servant,

J. W. NICKOLL.

RECENT AMERICAN PATENTS. (Selected from the Franklin Journal, for February.)

MAKING SHOES, AND RENDERING THEM IMPERVIOUS TO WATER, Ernst G. Augustine, New York. The soles, we are told, "may be made of plaited flax, hemp, or the inner bark of the linden tree. For the upper

part any kind of cloth may be used, and the shoes lined with linen or cotton. The soles are then varnished or covered with the following composition :-One quart of flax-seed oil, two ounces of rosin, half an ounce of white vitriol, which must be boiled together for half an hour. After which take four ounces of spirits of turpentine, and two ounces of white oak saw-dust, which has been exposed twenty-four hours to the sun: mix these ingredients well together, and put them on the soles of the shoes with a brush, or in any other way, which when dried will render them impervious to water.'

The claim is to "the above-described method of making shoes and rendering them water-proof." We do not discover any method of "making shoes" contained in the foregoing description.

CLEANING WOOL FROM BURRS. &c., M. N. Simpson, Boston, Massachusetts. -After giving a description of the machine intended to be used, the patentee observes, that wool from South America, and indeed almost all wools, have more or less of a vegetable substance, called burrs, so attached to it, that it is not taken out by washing, and therefore the only mode of cleaning the wool has been by hand, until about two years since, a mechanic of the city of Boston. Mr. Lemuel Couillard, jun., invented a machine for the purpose, which performed the part of taking out the burr very well, but was set aside from the injury the staples received. The machine for which I now wish a patent performs the work of taking out the burr without any injury to the fibre. The wool should in the first place be well pinched by a common wool-pincher, with the burr in it, and in this state the machine receives it; it is placed by the operation on the feed- belt, which when the machine is in operation is conducted to the draw rolls, which revolve very slow, and as the wool is carried through the draw rolls, the card cylinder takes it in small quantities in a thin state, as it revolves with so much greater rapidity than the feedrolls, and carries it in a continued direction by the clipper-frame, which is placed nearly in contact with the surface of the teeth; the burrs and all foreign substances are stopped by the blade of the clipper-frame, and the swift revolution of the clipper knocks them off. The wool continues in the teeth of the card-cylinder, and is overtaken by the fan which is placed on the opposite side of the

clipper-frame, and is by the fan blown or taken from the cylinder, and deposited in a clean state in the room which may be made for the purpose."

It is stated that the machine may be much varied in form whilst the same effect will be produced; and the patentee says, "I do not therefore claim as my invention any particular form of machinery to effect the object of detaching burrs or other foreign substances from wool, but claim the application of knocking, blowing, brushing, or striking the burrs or other foreign substances from the surface of the card-teeth, or any other kind of teeth."

We think this claim may prove too broad, as Mr. Couillard some time ago claimed, among other means, the "blowing or striking them off," when properly exposed; it may be, however, that in the present machine the removal being effeeted from," the surface of the card-teeth," may so far modify the thing as to prevent the one patent interfering with the other.

BENDING OR SETTING FELLOES FOR THE WHEELS OF CARRIAGES, Edward Reynolds, Haddonfield, New Jersey. The patentee says, "What I claim as my invention is the machine, or apparatus, as herein described, and may properly be denominated revolving cylinders, to be used for the bending of felloes for carriages and waggons of all descriptions; sleigh-runners; iron tires for wheels; coopers' set-hoops, vessels' masthoops, &c. In which machine two cylinders are employed, operated together by means of certain accessary parts, in the manner, or upon the principle, herein set forth."

We think the machine described well adapted to the bending of timber for rims for wheels. It consists of two wheels in a strong. frame, the peripheries of the wheels being nearly in contact with each other; the timber, prepared by boiling, or steaming, is to be bent round one of them, by turning the other, which presses forcibly upon it. An iron band laps round the outside of the bent timber, to prevent its checking; and there are proper staples, and other appendages, for the management of the process.

ROLLING UP CURTAINS, MAPS, &c., Henry Lawson, Boston, Massachusetts. - The handle by which the curtain, &c. is to be rolled upon its roller, is made much in the form of the old fashioned bell-pull, and has a small sheeve, or pulley, at its upper end ; a cord, one end of which is fastened to and winds round the end of the roller, passes through the pulley, and has its other end fastened to a pin, or other attachment, above this whole arrangement, it will be seen, is exactly similar to the hanging the weight of a common eight-day clock.