NIT
NIT
( 155 )
49 Potafh33 Nitric acid18 Water
ioo
According to Wenzel ioo parts of nitre•ontain
48.13 Potafh51.87 Acid and water
100.00
But according to Kirwan 100 parts of.cryf-tallized nitre dried at 70° Fahr. are compofed
of
51.8 Potafh44 Acid'
4.2 Water
100.0
and this eftimate being incidentally confirmedby other experiments of Berthollet and of Keir,is probably very near the truth, s
The ufes of nitre are very important. It isemployed in prodigious quantities in the manu-facture of gunpowder, and in all kinds of pyro-technics! compofitions. It is the only fait fromwhich nitric acid is habitually made, both inthe large and fmall way ; it is alfo largely con-fumed in the preparation of fulphuric acid fromthe combination of fulphur. When mixedwith common fait it adds to the efficacy of thislatter in preferving animal fiefh from decay;it is employed by the glafs-makcr and the gold-fmith, and is in conftant ufe in the laboratory.
* * * •#
We now proceed to treat of the natural hif-tory and manufacture of nitre, as carried on invarious countries, but chiefly in France , whereits production has been more an object of pliilo-fophical inveftigation than in any other country.
Nitre may be confidered both as a naturalsmd artificial produCt. Native nitre minera-logically fpeaking, is a fubftance of very recentformation. It appears to occur in two differentrepofitories : the firft of thefe is limeftone, andthe fecond vegetable foil. The calcareous repo-utory is either a peculiar variety of fecondaryfloetz limeftone, or calcareous tufa, or chalk, orin urated marl. In thefe rocks it occurs as athin granular cruft, or an efflorefcence of minutefpicular cryftalf overfpreading the outfide, vndt Kirwan on Acid6 (Additional Obfer.) p. 70. h
particularly lining the infide of the cavern*both natural and artificial, with which theferocks abound. Hence probably is derived itsancient name faltpetre (Sal peira, rock fait).Calcareous ftrata containing nitre, are found invarious parts of South America , in fome diftri£tsof France , in the county of Bamberg, and atHamburg near Wurtzburg . But the moftcelebrated repofitory of native nitre is the Puloof Molfetta, in the province of Puglia , in thekingdom of Naples. The Pulo is a deep cavityin the form of an inverted cone, produced bythe falling in of feveral large natural caverns,and communicating laterally with other cavernsboth natural and artificial, that yet remain entire.All the ftrata in which thefe excavations occurare of hard fecondary limeftone, abounding withthe remains of organized bodies. The wholeof thefe caves at the time when the AbbeFortis called the public attention to them, werelined with an efflorefcent cruft of nitre morethan an inch in thicknefs, which after beingfcraped off, was again renewed in the courfe ofa few days in conftant fucceffion. Thin frag-ments of ftone were often falling down, beingforced from their place by the cryftallizations ofnitre beneath them ; the fubftance of the rockalfo to the depth of a foot or more from thefurface, was richly impregnated with the faitwhich might be feparated by lixiviation; butfpecimens taken from a greater depth feem tocontain no nitre ready formed, at leaft boilingwater was incapable of diffolving out any. Itappears however from the teftimony of Dolom-ieu, that a piece of this rock after lying for twomonths in a dry cabinet, became covered witha thin cruft of nitre. Specimens of the nitrouscruft from the Pulo have been analyfed both byKlaproth 11 and Pelletier, ‘ and the refults agreefull as well as can be expefted in the exami-nation of a fubftance fo liable to flight variationsin its compofition.
IClapr.
425-5
2 .
254.5
3 ° 4 *
Pellet.
— 407.5 Nitre
— - Muriated potafh
26.7 Muriats
20.8 Sulphats, foluble in cold
water
— 9 6,. 7 Sulphat of lime.
986.0 — 961.714 — 38.3 Lofs