NIT

( 1 65 ) NIT

that of common nitte, except that it is fome-what more bitter.. It does not appear to occurnative, but may readily be prepared by fatu-rating nitric acid with carbonated foda and thenevaporating the folution to a pellicle : the crys-tals are depofited as the liquor cools.

When placed on a hot coal it firft flightly-decrepitates and is then decompofed like com-mon nitre, only with not fo vigorous a deto-nation. By expofure to the air it becomes Softand moift, without however absolutely deli-quiating.

It is Soluble by thrice its weight of coldwater, and in lefs than its weight of boilingwater. It is decompofed by the Sulphuric andother acids with the fame phenomena as com-mon nitre; it is alfo decompofed by potafh andbarytes, cauftic foda being liberated.

Lt is compofed according to Kirwan of53.21 Nitric acid40.58 Soda6.21 Water

100.

Nitrat of,foda is not applied to any ufe.

Nitrat of Ammonia. Nitrum Flammansof the older chemilts.

This fait is feldom if ever found native, andis produced in the laboratory by faturating dilutenitric acid by carbonat of ammonia, and evapo-rating. If the evaporating heat does not ex-ceed 100°, the liquor on cooling fhoots intotranfparent cryftals in the Shape of fix-fidedprifms, terminated by long fi’x-fided pyramids.But if evaporated at the heat of boiling water,it yields on cooling thin fibrous cryftals, or ifthe evaporation be carried nearly to drynefs, thewhole concretes into a eompaft fhapelefs mafs.

Mr. Davy a infers thefe three varieties ofnitrat of ammonia to be compofed as follows :2,co grains of folution of pure ammonia con-taining 50.5 grains of alkali faturated 385.5grains of nitric acid of 1306 fp. gr. containing190 grains of real acid, eftimated in the waymentioned under that article. This mixtureevaporated at 212° gave 254 grains of fibrousnitrat of ammonia. But from comparing thefpecific gravity of the mixture before evapora-tion . with that of a folution of another equalportion of the fibrous fait, it was found that8 grains of the fait were diffipated during theevaporation. The quantity of water in the254 ~r 8 grains of the fait, was 21.5 grains, andfcence ieo parts of the fibrous falt-are compofed

of about 72.5 nitric acid, 19.3 ammonia, and 8.2-water.

The prifmatic fait (or that produced by gentleevaporation at a heat not exceeding ioo°) iscompofed of about 69.5 per cent, of acid, 18.4-of ammonia, and 12.1 of water.

The other variety, the compact fait made-by evaporation to drynefs at a heat not ex-ceeding 300* contains according to this ablechemift 74.5 of acid, 19.8 of alkali, and 5. 7 ofwater. Some of the fait is diffipated during,evaporation.

In thefe three varieties the quantity of alkalibears nearly the fame proportion to the acid,and the difference is chiefly in, the water of cryf-tallization. During evaporation of the folutionat a heat below 100 0 fcarcely any lofs of fait isdetected ; at 212' the lofs is about 3 or 4 grainsper cent, and at the boiling point of the faturatedfolution (which is many degrees higher) thelofs is about 4 to 6 grains per ce?it.

This fait may alfo be made by the decompo-fition of fulphat of ammonia by nitre. Nitrat of ammonia and fulphat of potafh are formed,and if no more nitre be added than is fufficientfor the decompofition, a judicious evaporationand cryftallization, two or three times repeated,will feparate thefe two falts almoft entirely.Mr. Davy eftimates that 100 grains of fulphatof ammonia require about 134 grains of nitre,,and yield 91 grains of eompaft nitrat of am-monia.

This fait is deliquefeent in all its forms, and isextremely foluble in water. Its tafte is peculiar,and very pungent.

When the dry fait is heated fuddenly and ’ftrongly (as when a fmall quantity is dropped'on a red-hot earthen crucible) it inftantly melts, .takes fire and burns with great ebullition and ;hilling, and a red-blue flame, but without explo--fion, with nearly the fame appearance as whena lump of nitre is thrown on hot coals. Nitrat of ammonia is the only nitrat that deflagrateswithout the contaft of any carbonaceous or in-flammable matter, whence the immediate decom-pofition of the ammonia may be inferred, thehydrogen of the alkali furnifhing inflammablematter for the oxygen of the nitric acid. Thisfelf-inflaming property makes it neceffary toufe caution in heating any dry mixture of nitricacid and ammonia in elofe veffels. Jt has how-ever been examined in this way by Mr. Davy,,and the dry diftillation of this fait is now parti-cularly interefting, as it furnifhes that curious?gas the nitrous oxy 4 ,.

• Rdearchcb..