NIT

NIT

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cauftic ftate are by no means fo efficacious ascarbonat of lime. Thus it appears that threeconditions are requilite for the produ&ion ofnitrated lime (from which by the fubfequentaddition of carbonated potafh common nitre isreadily obtained] viz. animal matter in a ftate,of decompofition, atmofpheric air, or ratherthe oxygenous part of it, and carbonated lime.

Hie firib propofal for the conflruction ofartificial nitre beds came from Glauber. Thisable chemift refletfting on the circumftancethat earth which had been long expofed toexhalations from the dung and urine of fiieepand other animals, or in which animal bodieshad been buried was capable of affording nitreby lixiviation, concluded that this fait wascontained in animal matter: but finding thatvarious animal fluids fuch as urine and blood,afforded no nitre when recent, he was inducedto try the effect of putrefaction on them: forthis purpofe he filled an open veffel with blood,and expofed it to fpontaneous decompofitiontill nothing remained of it but a loofe earth,:from this by lixiviation he obtained a portion ofnitre, hence he concludes that the falts con-tained in recent animal matter are in an inertor as he calls it a dead ftate, till by long expo-fure to the air and fermentation they acquirefrom it a vital fpirit. m From the nitrous efflo-refcences on the plaifter of cellar walls heinferred that the faline bafe of nitre was alfocontained in certain earths; and becaufe thatpart of the plaifter in immediate contact withthe bricks, and therefore excluded from the air,afforded no nitre by lixiviation, he drew thefame conclufion as in the former cafe refpe&ingthe vivifying influence of the air in the forma-tion of nitre. It being a matter of commonnotoriety that earth when long impregnatedwith the lees of wine became rich in nitre, thiscircumftance together with other collateral ar-guments induced him to infer the prefence of.nitre in vegetables alfo. In purfuance of thistheory he propofes the following plan for theformation of nitre." Let a large fquare woodenvat be made open at top, and with a perforatedfalle bottom placed a few inches above the realbottom, and between the two bottoms let apipe with a flop cock be inferted fo as to dif-charge any liquor into a {hallow open refervoirfunk into the ground juft in the front of the vat:on the oppofite fide of the refervoir let anothervat fimilar to that already defcribed be placed,and, to compleat the apparatus, let a pump be'fixed in the refervoir by which its contents may* German. Profperit. part I. p. 103

be transferred to either of the vats that theworkman choofes. Every thing being compleatlet the vats be filled with horfes’, cows’, orfheeps’ dung mixed with leaves or any dry-vegetables: then draw a weak alkaline ley fromquicklime and woodafhes and pour it into oneof the vats till it ftands a finger’-s breadth abovethe other ingredients. In about 12 hours timeturn the cock and let the liquor drain into therefervoir, whence it is to be pumped again intothe other vat, and after 12 hours more return-ed into the refervoir. In the fpace of a fewdays the contents of the vats will heat andferment ftrongly: no further care is requiredtill the decline of the fermentation, which maybe known by the ceffation of the fteam: thematerials are then to be again drenched withthe liquor in the refervoir for 12 hours, and whenthis is again difeharged the fermenation willrecommence. This method being purfued forten or twelve months, (taking care to keep thevats filled with frefti portions of leaves and dungas the mafs fubfides] both the liquor and thecontents of the vats will be found to be veryrich in nitre.

The above method of Glauber’s defervesnotice as the firft attempt at the artificialmanufacture of nitre, although there is littledoubt that its fuccefs is greatly exaggerated, asis but too much the cuftom of this author,Another method propofed by the fame chemiftand the fuccefs of which is better authenticatedis the following. Conftruct a vault of framework of any climenfions and line it to thethicknefs of three or four inches with plaiftercompofed of the following materials, viz. onepart of quicklime, one of woodafhes, and twoof cow's or horfe’ dung with a fufficient quantityof urine to work it up to a proper confidence.This plaifter being carefully applied is to bedried by a gentle fire to be made under thevault, a fecond coating of the fame materials isthen to be put on, and thus by alternate dryingand plaifterinjf jjhe vault is to be made two orthree feet thick. Being now fufficiently ftrongthe wooden framing may be removed. Theplaifter in proportion as it dries is to be reftoredto a proper ftate of moifture by the applicationof urine, and in the fpace of a few months,more ©r lefs according to the warmth of the airand other circumftances, the whole infide ofthe vault will be covered with nitrous efflores-cences: by degrees the plaifter will be impreg-nated with nitre through its whole fubftance,at winch time the vault being broken down an JB Ditto, part III. p, 7.