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and the hollow formed by the bottom of the bottle was filled with clouds of fteam, which, after circulating in it with furprising rapidity 4 or 5 minutes, and after forcing out a good deal of air from under the bottle, began gradually to clear up. At the end of 8 or 10 minutes (when, as I fuppofed, the air remaining with the fteam in the hollow cavity formed by the bottom of the bottle, had acquired nearly the fame temperature as that of the fteam) thefe clouds totally difappeared; and, though the water continued to boil with the utmoft vidlence, the contents of this hollow cavity became fo perfectly invifible, and fo little appearance was there of fteam, that, had it not been for the ftreams of water which were continually running down its fides, I fhould almost have been tempted to doubt whether any steam was actually generated.

"Upon lifting up for an inftant one fide of the bottle, and letting in a fmaller quantity of cold air, the clouds inftantly returned, and continued circulating leveral minutes with great rapidity, and then gradually disappeared as before. This experiment was repeated feveral times, and always with the fame refult; the fteam always becoming visible when cold air was mixed with it, and afterwards recovering its tranfparency when, part of this air being expelled, that which remained had acquired the temperature of the fteam.

"Finding that cold air introduced under the bottle caufed the steam to be partially condenfed, and clouds to be formed, I was defirous of feeing what visible effects would be procured by introducing a cold folid body under the bottle. I imagined that if steam was a conductor of heat, fome part of the heat in the $797.

fteam paffing out of it into the cold body, clouds would of course be formed; but I thought if steam was a non-conductor of heat,-that is to fay, if one particle of fteam could not communicate any part of its heat to its neighbouring particles, in that cafe, as the cold body could only affect the particles of fteam actually in contact with it, no cloud would appear; and the refult of the experiment fhowed that steam is in fact a non-conductor of heat; for, notwithstanding the cold body used in this experiment was very large and very cold, being a folid lump of ice nearly as large as an hen's egg, placed in the middle of the hollow cavity under the bottle, upon a small tripod or ftand made of iron wire; yet as foon as the clouds which were formed in confequence of the unavoidable introduction of cold air in lifting up the bottle to introduce the ice, were diffipated, which foon happened, the steam became fo perfectly transparent and invifible, that not the fmalleft appearance of cloudinefs was to be feen any where, not even about the ice, which, as it went on to meit, appeared as clear and as tranfparent as a piece of the finest rock cryftal.

"This experiment, which I first made at Florence, in the month of November, 1793, was repeated feveral times in the prefence of lord Palmerfton, who was then at Florence, and Monf. de Fontana.

"In thefe experiments the air was not entirely expelled from under the bottle; on the contrary, a confiderable quantity of it remained mixed with the steam even after the clouds had totally disappeared, as I found by a particular experiment made with a view to afcertain that fact; but that circumftance does not render the refult of this experiment lets curious, on the contrary I think I

it tends to make it more furprising. It should seem that neither the mafs of fteam, nor that of air, were at all cooled by the body of ice which they furrounded, for if the air had been cooled (in mass), it seems highly probable that the clouds would have returned.

"The refults of thefe experiments compared with thofe formerly alluded to, in which I had endeavoured to ascertain the most advantageous forms for boilers, opened to me an entirely new field for fpeculation and for improvement in the management of fire. They showed me that not only cold air,

but alfo hot air, and hot fteam, and hot mixtures of air and ftean, are non-conductors of heat; confequently that the hot vapour which rifes from burning fuel, and even the flame itself, is a non-conductor of heat.

"This may be thought a bold affertion, but a little calm reflection, and a careful examination of the phenomena which attend the combuftion of fuel, and the communication of heat by flame, will show it to be well founded; and the advantages which may be derived from the knowledge of this fact are of very great importance indeed."

ACCOUNT of a METHOD of making SOAP of WOOL, with OBSERVATIONS respecting its USE in various ARTS. By M. CHAPTAL.

[From the ANNALES DE CHIMIE, and inferted in the Seventh Volume of the REPERTORY of ARTS and MANUFACTURES.]

"

I

Have already fhewn the manner of making, at all times, in every place, and at a fmall expence, a faponaceous liquor which may be conveniently ufed, inftead

of foap, for domeftic purposes. (See the. Report of Meffrs. Pelletier, d'Arcet, and Le Lievre, on the art of making foap*.) I fhall now prefent to the public a fupplement

to

"As that part of the report referred to by M. Chaptal appears to be of general utility, we shall here give a tranflation of it.

"A very good way of using foap is, to employ it in a liquid flate; that is, diffolved in water. In confequence of which, M. Chaptal propofes that faponaceous liquors fould be prepared, which may be used instead of solutions of foap; and, in order to be able to procure fuch liquors, at all times, in all places, and a fmall expence, he advifes one or the other of the following methods to be praftifed. We shall defcribe them exactly as M. Chaptal communicated them to us, with obfervations thereon, made by himself.

"First Method.

"Take the afhes produced from the combuftion of wood which has not been floated, and make a ley of them, according to the ufual manner; mix.ng with the ashes a handful or two of quick-lime, well pounded, or recently flaked. Let the ley ftand till it is grown clear, by the fettling or fwimming of the foreign fubftances contained therein; then pour it into another vefiel, and keep it for ufe. When it is propofed to make use of this ley, take any quantity of oil, and pour upon it thirty or forty times as much of the ley. Immediately a liquor as white as milk will be formed, which, by being well

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to my former work, inftructing them how to prepare, as a fubfti

tute for foft-foap, (which is at pre fent made ufe of in fulling almost

every

shaken, or flirred, lathers and froths like a good folution of foap. This liquor is to be poured into a washing-tub, or other veffel, and to be diluted with a greater or lefs quantity of water; after which, the linen, meant to be wathed, is to be steeped therein, te be rubbed, and wrung, in the ufual way.

« Obfervations.

"1. It is better that the ley fhould not be made until the time when it is to be used: if it is left to stand in open veffels, its power is weakened, and its nature is changed.

"2. Fresh wood-ashes are preferable to old ones, particularly if the latter have been expofed to the air; in that cafe, they have no longer their ufual power, and we muft, in order to make them ferve our purpose, mix with them a greater proportion of quicklime.

"3. Those afhes alfo are preferable which are produced from hard wood: thofe which are left after the burning of floated wood cannot be made ufe of with equal fucċefs.

"4. Fat oils, of a thick confiftence, are most proper for the purpofe here spoken of: fine thin oils are by no means fit for it.

5. If ftinking oil be made ufe of, it is apt to give a bad smell to the linen; this may be removed by paffing the linen carefully through a ftrong pure ley; but, in gene ral, this fmell goes off as the linen becomes dry.

6. When the mixture of oil with the ley is of a yellow colour, it must be diluted with water.

"7. When the oil rifes in the ley, and fwims upon the furface of it, in the form of fmall drops, it fhews that the oil is not fit for the purpose, not being thick enough; of elfe, that the ley is too strong, or not fufficiently cauftic.

"8. To prevent the quick-lime from lofing its power, and that we may always have fome to use when we want it, it may be broken into finall pieces, and kept în bottles well dried, and well corked.

"Second Method.

“Floated wood, which is made use of in many parts of France, produces ashes which contain very little alkaline falt, and which are confequently very improper for making leys; in that cafe, barilla, or potash, may be used instead of them.

"Take barilla, and break it into pieces about the fize of a walnut; put thefe into a veffel of any kind, and pour upon them twenty times their weight of water: the water is to be left upon the barilla till it appears, by putting a little upon the tongue, to be flightly falt.

"Some oil is then to be put into an earthen vessel, and forty times as much of the barilla-ley is to be poured upon it: the mixture, which foon becomes milky, is to be well fhaken, or firred; and, after being diluted with more or less clean water, according to its ftrength, and the purpofe for which it is intended, is to be made ufe of like a folution of foap in water.

"Instead of barilla, pot-afh may be employed, but it requires a small quantity of pounded quick-lime to be mixed with it.

" Obfervations:

1. Alicant or Carthagena barilla may be used without any mixture of lime; but the bad barilla of our country requires to have mixed with it a greater or lefs proportion of lime, according to its degree of-itrength and purity.

2. When barilla, of whatever kind it may be, is in a state of efflorefcepce, it can

not be employed without a mixture of lime,

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* 3. If

every kind of woollen ftuff,) a kind of foap which cofts little, and which may be eafily made in every woollen manufactory.

"In all manufactories of cloth, blankets, and other woollen goods, It is the custom to full the ftuff, as foon as it comes from the loom. The intention of this operation is, not only to fcour the cloth, &c. but alfo to render it more compact; and, in performing it, about thirty pounds of foft-foap are ufed to eighty pounds of woollen ftuff. In the fouth of France, before the revolution, foft-foap coft twenty livres the hundred weight. A great part of our oil, and also of that of Italy, is confumed in making it; fo alfo are the wood-afhes of the fires ufed for domeftic purposes, in thofe countries where it is made.

"From what has been faid, it is obvious how advantageous it would be to the manufacturer, and to commerce in general, to be able to fupply conveniently the place of foft-foap, by an article, the preparation of which is neither difficult nor expenfive. Befides the faving which would take place in the manufacturing of woollen goods, great advantage would arife fro the afhes of our wood-fires being left, either for domeftic ufes, or for falt-works, or for manufactories of green glafs; and, at the fame time, the oil now used in making foap would remain, to be wholly enployed for purpofes wherein it is impoffible to find a substitute for it. In all times, both the manu

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facturer and the government havě fought how to get rid of the above mentioned inconveniences. Fullers earth, pure alkalies, and other things, have by turns been made ufe of. The firft performs the operations of bleaching and fulling very imperfectly: the fecond diffolve the cloth; and the manufacturers of Lodeve ftill recollect, with terror, a quack fent there by the go. vernment, fome years ago, who propofed to make ufe of mineral alkali or barilla, instead of soap.

"To the inconveniences already mentioned we may add, that inftead of rendering the cloth fufficiently foft and pliable, the fubftitutes juft fpoken of leave it in a degree of harthnefs, which nothing but foap completely removes. It is neceflary, therefore, that any fubftance propofed to be used, instead of softfoap, fhould poffefs the power of fcouring, of fulling, and of foftening, the cloth. The compofition I an now about to defcribe unites all thefe advantages: experiments have, by my defire, been made with it, at Lodeve, by M. Michel Fabriguette; a perfon as well verfed in philofophical purfaits as in manufacturing of cloth.

"The whole procefs confifts in making a cauftic alkaline ley or lixivium, with wood-athes or potafh; in caufing the ley to boil; and then diffolving therein as great a quantity of old woollen rags; or threds of cloth, as the ley will diffolve. By this means a kind of foftfoap is produced, of a greyith-green

3. If the barilla-ley is o ftrong, the oil is apt to swim on its furface; it must then be diluted with a proper quantity of water.

4. Fat oil is molt fit for this purpose: fine light oils fhould not be used.

5. When the faponaceous liquor is grea, and the linens washed in it are fo likewife, they must be paffed through a pure barilla-ey, to have their greatness removed; which ley thould first be warmed a little, to encrease its effect.

6. When the water which was poured upon the barilla is all ufed, frefa water may be poured upon the remaining barilla. This water will acquire a faline tafte, like the SR: thus, the fame barilla may ferve for feveral fucceflive operations.

colour,

1

Colour, the ingredients of which are well combined with each other, and which is very foluble in water. It has an animal fmell, which, however, the cloths get rid of, by being wafhed, and expofed to the

air.

"The various experiments I have made on this fubject have been attended with the following refults:

"1. As foon as the wool is thrown into the boiling ley, its fibres adhere to each other, and a very flight degree of agitation is fufficient to render its folution complete.

"2. In proportion as fresh wool is added, the ley gradually acquires colour and confiftence.

"3. The foap has more or less colour in proportion to the cleannefs and whitenefs of the wool made ufe of.

4. Hair of a coarfer kind, which happens to be mixed with the old wool, is diffolved with more difficulty.

5. The quantity of wool which ley is capable of diffolving depends upon its ftrength, its caufticity, and its degree of heat. Two pounds, three ounces, and three quarters, of cauftic alkaline ley, at twelve degrees of concentration, and at the boiling-heat, diffolved ten ounces and a half of wool. The foap, when cold, weighed one pound and four ounces.

"A fimilar quantity of alkaline ley, of the fame degree of caufticity and heat, in which I diffolved four ounces of wool, did not thereby acquire fufficient confiftence to be capable of being used for the various purposes for which this foap is intended.

"Another fimilar quantity of ley, of four degrees of concentration, could not diffolve more than

two ounces and feven drams of wool. The foap was of a good confiftence, and, when cold, weighed fourteen ounces.

"6. In proportion as the wool is diffolved in the ley, the folvent power of the alkali grows weak, and at laft it will diffove no more. When we obferve that the wool, upon being ftirred in the liquor, is no longer diffolved, it is then time to flop the process.

"I fhall now point out what means are to be employed, in every woollen manufactory, to prepare the foap which will be wanted in it.

"On the Choice and Preparation of the Materials.

"The materials requifite to form this foap are only two; alkaline subftances, and wool.

"The alkaline fubftances may be procured from the afhes of any fires where wood is burnt; and the ley is to be made according to the common well-known procefs.Quick-lime is to be flaked with a fmall quantity of water, and the pafte formed thereby is to be mixed with the athes, (they being first paffed through a fieve,) in the proportion of one-tenth part of quicklime, by weight, to the quantity of afhes made ufe of. The mixture fhould be put into a ftone veffel; (as wooden veffels not only colour the ley, but are themfelves much injured by it;) and water is then to be poured upon it, in fuch quantity as to cover it, and rife fome inches above it. Thefe are to be left together for a certain time, and then the ley is to be drawn off, by an aperture, made for that purpose, at the bottom of the veffel. It is beft. not to draw off the ley, till the moment when it is to be used: its ftrength fhould be from four to fifI 3

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