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N G. B I. E A 0 H down, and lodge in the cloth, and the putrefadtion which bleaching allies as a compofition of lime and alkaline falts, then will weaken it. This appears from the fol•we muft difcover a frelh fund for the depofition of this lowingbegins experiment. abforbent earth. The common cauftic, a compofition of 16. A piece of cloth, weighing 42. gr. was this very kind, foon converts itfelf, if expofed to the o- laid“ inSep. butter-milk unwhigged. Novem. 15. The milk pen air, into' a harmlefs earthy powder. putrified fmell. The cloth was a little whiter, .Frequent buckings and bleachings load the cloth with had avery tender ; and weighed, when well walhed in th's fubftance. It becomes then necelfary to take it out. but water and dried, 40 gr.” No walking can do that, becaufe earth is not foluble in warm the fours made of bran, rye-meal, 6c. ought to water. Nothing but acids can remove it. Thefe are be All before ufe ; for by this means fo much time attrafted by the abforbent earth, join themfelves to it, willprepared be faved. Befides, when the water is poured upon and compofe a kind of neutral imperfedt fait, which is the and bran, as is done in the management of foluble in water ; and therefore eafily walked out of the coarfecloth, cloth, the linen is not in a better fituation than if clo'th. The acid liquors commonly ufed are butter-milk, it had been taken up wet from .the field; and by this which is reckoned the bell:, four milk, infufions of bran, means the acid particles cannot penetrate fo deep. Arye-meal, 6c. kept for fome days till they four. Sour gain, this method of mixing the bran with the cloth, whey is thought to give the cloth a yellow colour. attended with yet worfe confequences. All veThe linen ought to be dried before it is put in the may befubftances, when much prefled, fall into the putreffour, that the acid particles may penetrate, along with getable and not the acetous fermentation. This often hapthe v/atery, through the whole. A few hours after it cent, to the bran prefled betwixt the different layers has been there, air-bubjes arife, the liquor fwells, and a pens the linen, which muft weaken the cloth. Hence, thick fcum is formed ; mahifcft ligns of a fermentation. oh fours Ihould be prepared before the cloth is fteeped in The following experiment, fays Dr Home, ihews the all them; and none of the bran or meal Ihould be mixed degree of heat which attends it. cloth. “ May 25. I put a thermometer of Fahrenheit’s in- withThethefours are ufed ftrongeft at firft, and gradually to fome butter-milk, of which the bleachers were comtill the cloth has attained to its whitenefs. In pofing their fours, and which flood in a vat adjoining to weakened firft fourings, there is more of the earthy matter in another, where the milk was the fame, and the fouring the from the many buckings it has undergone, procefs had been going on for two days. After the the cloth, what there can be afterwards. As the quantity of thermometer had been twenty minutes in the butter- than matter decreafes, fo fhould the ftrength of the milk, the mercury Hood at 64 degrees. In the fouring this There is not, however, the leaft danger, at any vat it rofe to 68 degrees. An increafe of 4 degrees four. time, from too ftrong a four. Ihows a pretty brilk inteftine motion “ To what are all thefe effefts owing ? To the ace- What is molt wanted in this operation is a more exand cheaper method of obtaining the fame end. tous fermentation going on in thofe vegetable liquors, peditious it takes five or fix days, it retards the whitening of whofe acids, extricating themfelves, produce heat, in- As doth confiderably; and as bleachers are obliged to teflinc motion, and air-bubbles. As the change is flow, the fend for milk to a great diftance, it becomes very dear. the procefs takes five or fix days before it is finilhed. This makes them keep it fo long, that, During this time the acid particles are continually uni- when laftufed,confideration it can have no good effeft; perhaps it may ting themfelves to the abforbent earth in the cloth. That have a bad one. this fermentation goes on in the Lquor alone, appears There confideration that may lead us to Ihorten from this confideration, that the fame effe&s, viz. air- the time. is one It is obferved, that the fouring procefs is bubbles, and fcum, are to be feen in the butter-milk a- fooner finilhed in, warm than in cold weather. Heat lone. The only effedt then it has is, by the fmall de- quickens the fermentation, aiding the inteftine mogree of heat, and inteftine motion, which attend it, to tion. The vats therefore byIhould not be buried in the aifift the jun&ion of the acid and abforbent particles. ground, as they always are, which muft keep them cold; We Ihall prefently fee, that this procefs may be carried there Ihould rather be pipes along the walls of the room, on, to as great advantage, without any fermentation; to give it that degree of heat, which, on trial, may be and therefore it appears not abfolutely neceflary. to anfwer beft. There are few days in fummer fo “ When thefe abforbent particles are fully faturated, found hot as is neceffary; and the beginning and end of the the remaining acids may unite with, and have fome fmall feafon much too cold. That this is no ideal effedt in extradling the colouring particles. This appears fcheme,isthebyfollowing faft is a fufficient proof? There are from the two following experiments. vats in Salton bleachfield, adjoining to a partition“ Sept. 20. A piece of cloth which had been fteep- two wall, at the back of which there is a kitchen fire. In ed, weighing 414- gr. was put into a half-pound of but- thefe the fouring procefs is finilhed in three days, ter-milk, whigged, and well foured, by a mixture of whereasvatsit lalls water, and by boiling. Sept. 24. When taken out, and the fame room. five or fix days in the others placed round walked in water, it appeared a very little whiter. The This improvement, though it Ihortens the time of mineral acids, as will appear afterwards, whiten cloth, fouring a very little, yet is no remedy againft the fcareven though they are very much diluted. “ Juft before the acetous fermentation is finilhed, the city and dearnefs of milk fours. Such a liquor as would cloth Ihould be taken out; otherwife the fcum will fall ferve our purpofe, mult be found either among the vegetable
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