NIT

NIT

C 157 )

fait by a fimilar treatment. In confequence ofthis difcovery all thefe fubftances were claimedby the crown in mod of the countries of Europe ,and granted to focieties of faltpetre-makers, in-corporated for the purpofe of fupplying thepublic magazines of the country with this indif-penfable commodity. England and Hollandwere foon able to fupply themfelves at an eafyrate with nitre, by means of their commercialconnexions with India and China , and thereforeattended only a very fliort time to the domefticpreparation of this fait. France, Germany ,and the Northern Hates of Europe on the otherhand, importing but a fmall quantity of nitrein proportion to their wants, have always encou-raged its manufacture by every method intheir power. In the former of thefe countriesefpeciaily, the privileges of the faltpetre-makerswere fo extenfive and fo rigoroufly enforced, asto occafion much petty tyranny and vexation,befides operating as a direCt discouragement toagriculture. Thefe manufacturing companieswere allowed to take away without compenfa-tion all the nitrous foils that they could difcover:hence when a houfe was pulled down, fuch partof the old materials and foundation foil as fuitedtheir purpofe was feleCted from the reft andcarried off by them •, they had alfo the right ofdigging up once a year the earthen floors ofevery out-houfe, and in fonie provinces even ofthe inhabited cottages: the farmer’s yards werefubject to the like troublefome vifitations, bywhich he was deprived of a confiderable quantityof his beft manure ; and every parifh or diftriClwas obliged befides to furnifli a certain amountof wood-aflies. Thefe terrible means of annoy-ance were placed by the crown in the hands ofthe farmers general, and by them were entruftedto inferior agents, more difpofed to exercife themfo as to obtain from thofe in their power a pecu-niary compofition, than to exert their privilegesfor the public advantage; the confequence ofwhich was that notwithftanding the trouble andextortion by which individuate were thus fe-verely haraifed, the annual produce of nitre atthe acceffion of Turgot to the miniftry, fcarcelyexceeded one half of what it had amounted tohalf a century before. An important reformhowever was introduced by this able ftatefman,the privilege of digging up the floors and cellars°f inhabited houfes was aboliflied, the requifi-ttons of fluel and wood-afhes weye reftrained,and tbe adminiftration of this department wastaken from the farmers general, and entrufted*° j* P art * cu l ar commiflion, of which Lavoifierand Llouet were leading members; a confide-

rable fum of money was placed at the difpofalof the Royal Academy of Sciences, to be diftri-buted as prizes by this body to the authors ofthe beft memoirs on the preparation of faltpetre,in confequence of which various importantchanges took place in the management and con-ftruction of artificial nitre-beds, and the refiningof their produce. By thefe means the yearlyamount of nitre made in France was increaiedduring the period from 1775 to 1785, from1,800,000 lbs. to 3,500,000 lbs. Four yearsafter this period the Revolution war com-menced, for the fupply of which a prodigiousquantity of gunpowder was demanded, whileall the requifite nitre was obliged to be drawnfrom domeftic fupplies. To meet this exigencythe knowledge and perfonal fupeffntendanceof the ableft chemifts of Paris was dire£ted tothis important object, and in the fpace of a veryfew years the produce of nitre was more thanquadrupled, and a fimplicity and expeditionintroduced into the refineries of this fait, thatfeem to have brought its manufacture nearlyto perfe£tion.

In our account of nitric acid we have fhownthat the component parts of this fubftance areazot and oxygen, we have alfo fhown in anotherplace that animal matters in general contain alarge quantity of azot combined in various pro-portions with hydrogen, carbon and other fub-ftances. When the decompofition of animalmatter by means of the putrefactive fermenta-tion takes place, its elements enter into newcombinations with each other and for the moilpart aHume the gafeous form. Now althoughazot like feveral other bodies when it has com-pleatly acquired the ftate of elallic fluidity is-but little difpofed to combine with oxygen atthe ufual atmofpheric temperature, yet when inits nafcent ftate and'particularly when mixedat the fame time with eafily ccmbuftible fub-ftances it unites with oxygen without muchdifficulty. Hence it is obvious how nitrous acidor more probably nitrous vapour is produced bythe contact of atmofpheric air and putrid gas.But the acid is produced flowly, and in propor-tion as it forms will fly off together with theother volatile ingredients, except it meets withan alkaline bafe to combine with into a neutralfait. It might feem, a priori, a matter of perfectindifference, as far as the mere formation anddetention of nitrous acid is concerned, whetherone alkaline fubftance or another was employedfor this purpofe, but experiment has fhown, aswe fhall detail more at large prefently, that theproper fixed alkalies, whether in a mild or