cefs: which is attended with little or no trouble, and is fo fimple, that any perfon may perform it with great ease. Let a glass bottle be half filled with a mixture compofed of one part of red-lead or minium, and three parts of common muriatic acid. Let the bottle be immediately clofe with a glafs ftopper; and then fet. in a cool dark place. A certain degree of heat, which fpontaneoutly takes place in the mixture, fhows that new combinations are forming in it. The red-lead gives out a great part of its oxygen, which combines with the acid, caufing it to acquire a beautiful gold colour, and the peculiar fmell of oxygenated muriatic acid. A fmall portion of. lead is diffolved in the acid; but this does not at all diminish its power. It fhould be obferved, that the bottle used for this purpofe must be a very ftrong one; otherwife the elaftic vapour which arifes might burft it, especially if the ftopper is. firmly to be. mly fixed in, as it ought to In order to make ufe of the liquor, prepared as above, take a large pane of glais, and fix upon its edge a fort of border of wax, about an inch in height, and equally high all round. In this manner a kind of trough is made, in which the print is to be foaked, for three or four days, either in freth urine, or in water mixed with a fmall quantity of ox-gall. At the end of that time, the liquor is to be poured off, and its place fupplied with warm water, which is to be changed every three or four hours, until it comes off quite clean. If there is any dirt of a refinous nature upon the print, it may be removed by wetting it with a little alcohol. When the print is thus cleaned, let all the moisture drain from it, and (having placed it again upon the pane of glafs) pour upon it a fufficient quantity of the muriatic acid, oxygenated by the red-lead, to cover it. Another pane of glass, of the fame fize as the firft, may be placed upon the border of wax, to prevent any inconvenience from the dilagreeable finell of the acid.— The most yellow print, by this treatment, will be feen gradually to refume its original whitenefs; and one or two hours will be fufficient to produce all the effect that can be defired. Nothing then remains, but to pour off the acid, to wash the print, two or three times, in pure water, and to dry it in the fun." Defcription of a Liquor for discover- Tfulphur and hepatic air pof- fefs, of precipitating lead of a black But, in examining wines which are fufpected to be adulterated, this liquor can by no means be trufted to, becaufe it precipitates iron of the fame colour as it does lead, which is fo poifonous a metal. For this reafon, many refpectable winemerchants have been thought guilty of adulterating their wines, to the great injury of their character. Confequently there was ftill wanting a teft. or re-agent that should If one part of the above liquor be mixed with three parts of the wine meant to be examined, the fighteft impregnation of lead, copper, &c. will be immediately dif covered,. by a very perceptible black precipitate. But, if the wine contains iron, the liquor will have no effect upon that metal. point out, in wines, the prefence of fuch metals only as are injurious to health. This property the following liquor poffeffes, as it precipitates lead and copper of a black colour, arfenic of an orange colour, &c. It does not, however, precipitate iron, which frequently, by various means, gets unobserved into wines, but which is generally harmlefs, and in many cafes falutary, to the human frame. Preparation of the new probatory liquor, and adding to it a little falt Liquor. Mix together equal parts of oifter-fhells and crude brimftone, both finely powdered: put the mixture into a crucible, and place the crucible in a wind-furnace. When it is heated, let the fire be fuddenly increased, till the crucible becomes of a white heat, in which state it is to-be continued for about a quarter of an hour. The mais, when cold, is to be reduced to powder, and kept When the above precipitate has fubfided to the bottom, we may find out whether the wine contains any iron, by decanting the clear of tartar: if there is any iron in the wine; the liquor will immediately turn black. Wines which are pure and unadulterated, remain clear after the addition of this liquor. On the Art of cleaning Woollen and other Cloths. By M. Chaptal; from the Bulletin des Sciences. HE art cloths In order to prepare the liquor, Tofas, off, annowledge of one hundred and twenty grains of the above powder, and one hundred and eighty grains of cream of tartar, are to be put into a very firong bottle, which is to be filled up with common water, that has been previously boiled for about an hour and then fuffered to cool. The bottle must be immediately corked, and afterwards fhaken from time to time. When it has remained ftill for a few hours, the clear liquor must be decanted into finall phials, capable of holding one ounce, into each of which, twenty drops of fpirit of fea-falt have been previously dropped. The mouths of the phials must then be well clofed with ftopples, compofed of wax mixed with a finall quantity of turpentine. the various fubftances which can occafion_fpots upon them. Secondly, That of the fubftances to which we must have recourfe in order to remove thofe fubftances, when depofited upon the cloth.Thirdly, That of the manner in which the colours of the cloths will be affected, by the re-agents meant to be employed for the removal of the pots. Fourthly, That of the manner in, which the cloth itfelf will be affected by the above reagents. Fifthly, We thould know how to reftore the colour of the cloth, when it is changed or rendered faint. Of the fubftances which occafion pots upon cloths, tome are eafily known by their appearance; for inDd 4 flance, A stance, grease of every kind. Others produce more complicated effects, fuch are, acids, alkalies, perfpiration, fruits, urine. The effects of acids upon blacks, purples, blues, (except thofe produced by indigo or by Pruffian blue) and fome other colours, and upon all thofe fhades of colour which are produced by means of iron, archil, and aftringent fubftances, is to turn them red. They render yellows more pale, except that produced by arnatto, which they turn to an orange colour. Alkalies turn fcarlet, and all reds produced by brazil or logwood, to a violet colour; they turn green (upon woollen cloths) to yellow; and they give a reddish caft to the yellow produced by arnatto. The effect of perfpiration is the fame as that of alkalies. Spots which are produced upon cloths by fimple fubftances are eafily removed by well-known means. Grealy fubftances are removed by alkalics, by foap, by yolk of egg, or by fat earths. Oxides of iron, by nitric or oxalic acid. Spots occafioned by acids are removed by alkalies, and vice verfa. Spots caufed by fruit, upon white cloth, are removed by fulphureous acid, or, what is ftill better, by oxygenated muriatic acid. But, when the fpots are of a complicated nature, various means muft be employed, fucceffively; thus, to remove a spot occafioned by the coom of carriage-wheels, we muft firft diffolve the alkali by fome of the means above-mentioned, and then take away the oxide of iron by oxalic acid. The colours of the cloths are often injured by the re-agents made ufe of; in order to reflore them, we muft thoroughly understand the art of dying, and know how to modify the means according to circumftances. This is fometimes difficult, because it is neceffary to produce a colour fimilar to that of the reft of the cloth, and to apply that colour to a particular part only; fometimes also, the mordant which fixed the colour, or the bafis which heightened it, has also been de ftroyed, and must be reftored. is evident that, in this cafe, the means to be employed depend upon the nature of the colour, and that of the ingredients which produced it; for it is well known that the fame colour may be obtained from very different substances. It Thus, when after having made ufe of an alkali, to remove an acid fpot upon brown, violet, or blue cloth, &c. there remains a yellow fpot, the original colour is again produced by means of a folution of tin. A folution of the fulphate of iron reftores the colour to thofe brown cloths which have been dyed with galls. Acids give to yellow cloths, which have been rendered dull or brown by alkalies, their original brightnefs. When black cloths, dyed with logwood, have any reddifh fpots occafioned by acids, alkalies turn fuch fpots to a yellow cor lour, and a little of the aftringent principle makes them black again. A folution of one part of indigo in four parts of fulphuric acid, properly diluted with water, may be fuccefsfully employed to reffore a faded blue colour upon wool or cotton. Red or fcarlet colours may be reftored by means of cochineal, and a folution of muriate of tin, &c. The choice of re-agents is not a matter of indifference; vegetable acids are generally preferable to mineral 1 mineral ones. The fulphureous acid, however, may be used for fpots from fruit: it does not injure blue upon filk, or the colours produced by aftringents; nor does it affect yellow upon cotton. The volatile alkali fucceeds better than fixed alkalies in removing fpots produced by acids it is ufually made ufe of in the form of vapour, and acts quickly, feldom injuring the colour of the cloth. The means of removing fpots of greafe are well known; namely, alkalies, Fuller's-earth, effential oils diffolved in alcohol, a fufficient degree of heat to render the greafe volatile, &c. Spots of ink, or any other occafioned by yellow oxide of iron, may be removed by oxalic acid: the colour may be reftored by alkalies, or by a folution of muriate of tin. Such fpots may also be taken away by Oxygenated muriatic acid, when they are upon white cloth, or upon paper. The effects of alkalies and that of perfpiration is the fame; their pots may be removed by acids, or even by a dilute folution of muriate of tin. When the fpots are owing to various unknown caufes, we must have recourfe to compofitions poffeffing various powers; of which the following may be confidered as one of the most efficacious. Diffolve fome white foap in alcohol; mix with this folution four or five yolks of eggs; add gradually fome (pirit of turpentine, and then fir into the mixture fuch a quantity of Fuller's earth as will enable it to be formed into balls. The manner of using thefe balls, is to rub the fpots, previoufly wetted with water, with them; after which, the cloth is to be well rubbed and washed. By these means, all kinds of fpots, except those occafioned by ink, or any other folution of iron, will be removed. The washing of the cloth takes off its glofs, and leaves a dull spot, difagreeable to the eye. The glots may be reftored by paffing, in a proper direction, over the washed part of the cloth, a brufh wetted with water in which a small quantity of gum is diffolved, and then laying upon the part a fheet of paper, a piece of cloth, and a pretty confiderable weight, which are to remain there until the cloth is quite dry. Having been employed in examining the various fpecies and varieties of this plant, and being defirous to know every particularity concerning them, it was fcarcely poffible that I thould not seek to difcover how much vegeto-animal matter each of them was capable of furnithing; and whether any circumftance contributed to increase its proportion. I fhould have carried my inquiries upon this fubject (as well as upon many others) to a much greater extent, if fome particular circumftances had not stopped my progrefs. I can therefore offer only a few refults; but, trifling and imper fect fect as they are, they will not be totally ufelefs, if they fhould engage any other perfon to purfue the fubject, and to fulfil, better than I have been able to do, the end I had in view. After the harveft of 1791, I caufed to be ground twenty forts (fpecies and varieties) of wheat; fome of them were hard, the others foft. They were gathered from the fame foil, which was of an inferior quality. A fufficient quantity of each fort was ground; and fuch precautions were taken, as to prevent the poffibility of a mistake refpecting the flour produced from each particular kind of wheat. I fhall not at present speak either of the proportion of flour produced from thefe different wheats, or of the various kinds of bread I obtained from them; thofe will furnish matter for another memoir: in this, I fhall confine myfelf to what concerns the glutinous part. One pound of each fort of flour was made into a thick pafte, and afterwards worked for a long time with the hands, (according to the ufual manner,) under a very thin ftream of water, which ran, or rather dropped upon it; by this means, all the ftarch was feparated from the glutinous part. The latter I weighed while wet, and then dried it gently upon the cover of a faucepan, filled with boiling water, and placed over the fire. The refult of thefe operations was, firft, that two of the forementioned kinds of wheat, one of which had smooth ears of a reddish colour, with diverging beards, and grains of the ufual yellow colour, and a which ripened very early, and another kind which had white ears, alfo fmooth, without beards, with grains of a white colour, and which came originally from Philadelphia, gave each of them five ounces of glutinous matter from a pound of wheat; whereas, another kind, which had fmooth reddith ears, growing clofe together, with beards, and which feemed to be variety of that called bled de miracles, and another kind which had white ears, with ftrait beards, and long glumes, with hard long grains, and which is particularly diftinguifhed by the name of Polish wheat, (Triticum Polonicum, Linnæi) gave, only, the firft, two ounces, and the fecond, two ounces and a half, of this fubftance, per pound. From another kind, with purplish ears, bearded, and pubefcent, with hard fpotted grains, and which came originally from Nice and the Canaries, I obtained only half an ounce of the above matter per pound. The other forts, produced from four ounces to four ounces and a half per pound. Secondly that the flour of hardgrained wheats produced, in general, lefs glutinous matter than that of foft ones. Thirdly, that the glutinous part of fome kinds, after being dried, was more brittle than that of others; this was particularly the cafe with the bard-grained wheats. Fourthly, that, according to the remarks of M. Parmentier, in his work upon the vegetables ufed for food, the glutinous part lofes much of its weight by being dried. * Laftly, * Our colleague, M. Parmentier, expofed fome of the glutinous matter, divided into fmall pieces, to a very gentle evaporation, till it could be reduced into powder. He found that it lost three-fourths of its weight; and that the best grain contained only an |