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nity between that medium and sen. the danger of reasoning upon the fible bodies! a certain attraction or properties of a fluid whole existence cohesion by means of which bodies even is doubtful; and feeling that in general, or some kinds of bodies our kuowledge of the nature of in particular, may, some how or beat, and of the manner in which other, impede this medium in its it is communicated from one body operations in conducting or trans. to another, is much too imperfect porting heat from one place to an. and obscure to enable us to puriue otheri-It appeared from the re- these speculations with any prospect fult of several of my experiments, of success or advantage. of which I have given an account “ Whatever may be the manner in detail in my paper before mense in which heat is communicated rioned, published in the year 1786 from one body to anotber, I think in the lxxvith vol. of the Philosophie it has been sufficiently proved that it cal Transactions, that the couduet- palles with great difficulty through ing power of a Torriceliian vacuuni confined air; and the knowledge of is to that of air as 604 to 1000; but this fad is very important, as it en. I found by a subsequent experi- abies us to take our orcasures with ment, (see my second paper on heat, certainty and with facility for coue publihed in the Philosophical Tranf- fining heat, and dire&ting its opera. actions for the year 1792)-ihat 55 tions to useful purposes. parts in bulk of air, with i part of “But atmospheric air is not the fine raw folk, formed a covering for only non-conductor of heat. All confining heat, the conducting pow. kinds of air, artificial as well as na. er of which was to that of air as 576 tural, and in general alli elaitic 10 1284; or as 448 to 1000. Nuu', Auids, steam not excepted, seem to from the result of this last-mention- possess this property in as high a ed experiment, it Mouid seem that degree of perfection as atmospheric che introduction into the space air. through which the heat passed, of “That steam is not a conductor so small a quantity of raw silk as zo of heat, I proved by the following part of the volume, or capacity of experiment: a large globular bottle that space, rendered that space being provided, of very thin and (which now contained 55 parts of very transparent glass, with a narair and i part of Gilk) more imper. row neck, and its bottom drawn in. vious to beat than even a Torricel. ward so as to forn a hollow hemilian vacuum,-The filk must there- sphere about 6 inches in diameier; fore not only have completely de. this bottle, which was about Siuches

firoved the conducting power of in diameter externally, being filled athe air, but m s also at the same with cold water, was placed in a time have very sensibly impaired mallow dish, or rather plate, abuut that of the ethereal fuid which pro. 10 inches in diameter, with a fai bably occupies the interstices of air, bottom, formed of very thin sheet and which serves to conduct heat brass, and raised upon a tripod, and through a l'orricellian vacuum: for which contained a small quantity a Torricellian vacuum was a better (about is of an inch in depth) of conductor of heat, than this medi- water; a spirit lamp being then um, in the proportion of 604 to placed under the middle of this 448. But I forbear to enlarge plate, in a very few minutes the upon this subject, being sensible of Vater in the plate began to boil,

and

and the hollow formed by the bot. steam passing out of it into the cold tom of the bottle was filled with body, clouds would of course be clouds of steam, which after circu- formed: but I thought if steam was lating in it with surprising rapidity a non-conductor of heat, -that is to 4 or 5 minutes, and after forcing fay, if one particle of steam could out a good deal of air from under not communicate any part of its the bottle, began gradually to clear heat to its neighbouring particles, up. At the end of 8 or 10 minutes in that cafe, as the cold body could (when, as I suppoled, the air re- only affect the particles of steam acmaining with the steam in the hol tually in contact with it, no cloud low cavity formed by the bottoni of would appear; and the resnit of the the bottle, had acquired nearly the experiment thewed that steam is in same temperature as that of the fact a non-conductor of heat; for, steam) these clouds totally disap- notwithstanding the cold body used peared; and, though the water con- in this experiment was very large tinued to boil with the utmost vio and very cold, being a folid lump lence, the contents of this hollow of ive, nearly as large as an hen's cavity became to perfectly invisible, egg, placed in the mildle of the and so little appearance was there of hollow cavity under the bottle upIteam, that had it not been for the on a small tripod or stand mild of Itreams of water which were con iron wirs; yet as soon as the clouds tinually running down its fides, I which wvre formed in consequence should almost have been tempted to of the ur avoidable introduction of doubt whether any fteam was ac- cold air in lifting up the bolte to tually generated.

introduce the ice, weređutip ited, "Upon lifting up for an instant which sooo happened, tie iteun one fide of the bottle, and leiting in became to perfectly uansparent and a smaller quantity of cold air, the invisible, that noi the im left apcloud instantly returned, and con- pearance of clo'idinefs ; to be tinued circulating several minutes seen any where, not evin aburi the with great rapidity, and then gradı- ice, which, as it went on ta melt, ally disappeared as before. This cx. appeared is clear and as tra: frent periment was repeated several times, as a piece of the firelt rock crvital. and always with 'the same result; “This experiment, which I first the steam always becoming vilble made at Florence, in the month of when cold air was mixed with it, November, 1903, was repeated le. and afterwards recovering its trans. veral times in the presence of lord parency when, part of this air be- Palmerston, who was then at Flo. ing expelled, that which remained rence, and Monf. de Fontana. had acquired the temperature of the “In these experiments the air Steam.

was not entirely expelled from un" Finding that cold air introduc- der the bottle ; on the contrary, a ed under the bottle caused the steam considerable quantity of it remained to be partially condensed, and clouds mixed with the steam even after the to be formed, I was desirous of fee clouds had totally disappeared, as I ing what viâble etfeets would be found by a particular experiment procured by introducing a cold so- made with a view to ascertain that lid body under the bottle. I ima. fact; but that circumstance does not gined that it steam was a conductor render the result of this experiment of heat, some part of the heat in the less curious, on the contrary I think

1797.

it tends to make it more surprising. but also hot air, and hot steam, and It should seem that neither the mais hot mixtures of air and steam, are of itcam, nor that of air, were at all non-conductor's of heat; confe. cooled by the body of ice which quently that the hot vapour which they surrounded, for if the air had rises from burning fuel, and even been cooled in mass), it seems the flame itlelf, is a non-condu&or highly probable that the clouds of heat. would have returned.

“ This may be thought a bold * The result of these experi- affertion, but a little calm refle&tion, ments compared with those former and a careful examination of the ly alluded to, in which I had en. phenomena which attend the comdeavoured to ascertain the most ad. bustion of fuel, and the cornmunivantageous forms for boilers, open- cation of heat by flame, will fhew ed to me an entirely new field for it to be well founded; and the ad. speculation and for improvement in vantages which may be derived the management of fire. They from the knowledge of this fact are Thewed me that not only cold air, of very great impoi tance indeed."

Account of a Method of making Soap of Wool, with OBSERVATIONS

refpecting its Use in various Arts. By M. CHAPTAL.

[From the ANNALES DE CHImie, and inserted in the Seventh Volume

of the REPERTORY of Arts and MANUFACTURES.]

" I Have already thewn the man- of soap, for domestic purposes. (See

I ner of making, at all times, the Report of Messrs. Pelletier, in every place, and at a small ex. d'Arcet, and Le Lievre, on the art pence, a laponaceous liquor which of making soap*.) I shall now may be conveniently used, inflead present to the public a supplement

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« As chat part of the report referred to by M. Chaptal appears to be of general - utility, we shall here give a transation of it.

" A very good way of using soap is, to employ it in a liquid ftate ; that is, dissolved in water. In confequence of which, M. Chaptal proposes that faponaceous liquors should be prepared, which may be'uted instead of folutions of soap; and in order to be able to procure such liquors, at all times, in all places, and at a small expence, he advises one or the other of the following methods to be practised. We shall describe them exactly as M. Chaptal communicated them to us, with observations thereon, made by himsell.

First Method. « Take the ashes produced from the combustion of wood which has not been floated, and make a ley of them, according to the ufual manner; mixing with the ashes a hand. ful or two of quick-lime, well pounded or recently slaked. Let the ley ftand till it is grown clear, by the fettling or swimming of the foreign substances contained therein; then pour it into another vessel, and keep it for use. When it is proposed 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,

Thaken,

to my former work, instructing tute for soft-soap, (which is at prethem how to prepare, as a substi- sent made use of in fulling almost

every

shaken, or ftirred, lathers and froths like a good solution of soap. This liquor is to be poured into a washing.tub, or other veffel, and to be diluted with a greater or less quantity of water ; after which, the linen meant to be washed, is to be steeped therein, to be rubbed and wrung, in the ufual way.

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

« 2. Fresh wood-ashes are preferable to old ones, particularly if the latter have been exposed to the air ; in that cale, they have no longer their usual power, and we must, in order to make them serve our purpose, mix with them a greater proportion of quicklime.

“ 3. Those ashes also are preferable which are produced from hard wood : those which are left after the burning of floated wood cannot be made use of with equal success.

4. Fat oils, of a thick consistence, are moft proper for the purpose here spoken of: fine thin oils are by no means fit for it.

“ 5. If stinking oil be made use of, it is apt to give a bad smell to the linen; this may be removed by pafling the linen carefully through a strong pure ley; but in general, this smell 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 rises in the ley, and swims upon the surface of it, in the form of small drops, it thews that the oil is not fit for the purpose, not being thick enough; or elle, that the ley is too strong, or not sufficiently cautic.

“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 small pieces, and kept in 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 consequently very improper for making leys; in that case, barilla, or potash, may be used inftead of them.

"Take barilla, and break it into pieces about the size of a walnut ; put these 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 Nightly 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 shaken, or ftirred; and, after being diluted with more or less clean water, according to its ftrength, and the purpose for which it is intended, is to be made use of like a colution of soap in water.

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

Observations. “1. Alicant or Carthagena barilla naay be used without any mixture of lime; but the bad barilla of our country requires to have mixed with it a greater or less proportion of lime, according to its degree of Arength and purity..

“ 2. When barilla, of whatever kind it may be, is in a ftate of efflorefcence, it can. pot be employed without a mixture of lime.

“3. If

every kind of woollen stuff,) a kind fa&urer and the government have of soap wbich costs litrie, and which fought how to get rid of the abovemay be easily made in every wool. mentioned inconveniences. Fullers len manufactory.

earth, pure alkalies, and other o lo all manufactories of cloth, things, have by turns been made blankets, and other woollen goods, use of. The firft performs the it is the custom to full the stuff, as operations of bleaching and falling foon as it comes from the loom. very imperfectly: the second diffolve The intention of this operation is, the cloth; and the manufacturers not only to scour the cloth, &c. but of Lodeve still recollect, with ter. allo to render it more compa&t; ror, a quack sent there by the goand, in performing it, about thirty vernment, fome years ago, who propounds of soft-soap are used to posed to make use of mineral alkali eighty pounds of woollen Auff. In or barillz, instead of foap. the south of France, before the re. “ To the inconveniences already volution, soft-soap coft twenty livres mentioned we may add, that instead the hundred weight. A great part of rendering the cloth sufficiently of our oil, and also that of Italy, soft and pliable, the substitutes juft is consumed in making it; so also spoken of leave it in a degree of are the wood-athes of the fires used harfiness, which nothing but soap for domestic purposes, in those completely removes. It is neceí. countries where it is made. Cary, therefore, that any substance

“ From what has been said, it is proposed to be used instead of softobvious how advantageous it would soap, should pofless the power of be to the manufacturer, and to scouring, of fulling, and of softea. commerce in general, to be able to ing the cloth. The composition I supply conveniently the place of am now about to describe unites all foti-foap, by an article, the prepa. these advantages: experiments have, ration of which is neither difficult by my delire, been made with it, at nor expensive. Besides the saving Lodeve, by M.Michel Fabriguette; which wouid take place in the a person as well versed in philoso. manufacturing of woollen goods, phical pursuits as in manufacturing great advantage would arise from of cloth. the ashes of our wood-fires being " The whole process consists in left either for domestic uses, or for making a caustic alkali ley or falt-works, or for manufactories of lixivium, with wood-alhes or potgreen glass; and at the same time, alh; in causing the ley to boil; and the oil now used in making soap then diffolving therein as great a would remain to be wholly em- quantity of old woollen rags, or ployed for purposes wherein it is freds of cloth, as the ley will ditimpossible to find a substitute for it. solve. By this means a kind of foft

is In all times, both the manu. soap is produced of a greyith-green

“ 3. If the bariila-ley is too strung, the oil is apt to swim on its surface ; it must then be diluted with a proper quantity of water.

"4. Fat oil is moft fit for this purpose: fine light oils should not be used.

15. When the laponaceous liquor is grealy, and the linens washed in it are fo litewife, they muft be passed through a pure barilla-ley, to have their greafineis removed; which ley should first be warmed a little to increase its effect.

« 6. When the water which was poured upon the barilla is all used, fresh water and be poured upon the remaining barilla. This water will acquire a faline tafte, like the fickt: thus, the lane barilla may serye for several fucceffive opciations.

colour,

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