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fufliciently cool, the tops of the jars are to betaken off, and the cakes of fal-ammoniac thatare found adhering to them are to be feparated,and placed for a day or two-in a damp atmof-phere, which foftens their furface a little, andthus facilitates the removal of any fuperficialimpurities. Laftly, the cakes are packed up incasks for fale.

The following is a table of the proportionsof dry carbonat of ammonia afforded by differentfubftances:

Horn - - - -5-

Feathers - - T \-

Wool - - - i-

Soot - - - T ‘ r

Bones - - T ' TBlood - - - tt

Putrid urine - % - T

In common manufactories the dry carbonatyields rather lefs than ■§• of fal-ammoniac. Inmolt of the Scotch manufactories foot is ufedinftead of bones, thefe latter being only to beprocured abundantly in the vicinity of a verylarge town.

Muriat of ammonia prepared by any of theabove methods, poffeffes the following proper-ties. It has no fmell. To the tafte it is bitter,pungent, and urinous, and at the fame timecooling: its colour, when perfectly pure, is abluifh-white: its texture when fublimed is fi-brous : it is tough, moderately elaftic, and fome-what duCtile, and hence is not very eafily redu-cible to powder. Its primitive cryftalline form isthe regular oCtohedron, but when cryftallizedfrom its folution in water it is either in longtetrahedral pyramids or in flaky feathered crys-tals : when fublimed it fometimes forms rhom-boids, approaching very nearly to the cube:the former cryftals are fomewhat deliquefcent,but the latter, as well as every other fublimedvariety of this fait, are permanent in the air.Sp. gr. 1.42.

It is foluble in about thrice its weight ofwater at the ordinary temperature, and producesmuch cold during the folution: boiling watertakes up its own weight of this fait, part ofwhich as the folution cools is depofited in beau-tiful feathery cryftalsi.

When expofed to a dry heat fomewhat ex-ceeding that at which lead melts, it begins torife in the form of a white vapour (withoutprevioufly entering into fufion) which has apeculiar odour, and attaches itfelf to cool fur-faces. It is generally reprefented as under-going no change by this procefs, but accordingto Beaume, after repeated fublimations it begins

to be decompofed, a little ammonia being firftdifcharged, and afterwards fome muriatic acidgas.

Muriat of ammonia is decompofable withabftraCtion of its acid by the cauftic fixed alka-lies and by all the alkaline earths, more efpeci-ally if a moderate heat is applied : the ammo-nia is volatilized in the form of gas, and theacid remains behind in combination with theadded alkali. If a carbonated inftead of a purealkali is employed, and fublimation is had re-courfe to, the ammonia rifes in a mild or carbo-nated ftate.

Many of the metals and metallic oxyds arealfo capable of decompofing muriat of ammoniain the dry way, ammoniacal gas being difen-gaged, and the metal remaining behind in theftate of muriat. It is a remarkable circum-ftance that many metals when thus treated areconverted into muriated oxyds, although liquidmuriatic acid has no effect upon them, thusmercury when triturated accurately with fal-ammoniac and heated, difengages ammoniacalgas, and muriated mercury is the refult, ifhowever an excefs of ammoniacal muriat isprefent, this excefs combines with the muriatof mercury, forming the fal-alembroth, as wehave mentioned under the article Mercury.Silver by a fimilar treatment decompofes falammoniac, and is itfelf converted into lunacornea.

Sulphuric acid is capable of decompofingmuriat of ammonia by diftillation, the muriaticacid being volatilized and fulphat of ammoniaremaining in the retort. Nitric acid and mu-riat of ammonia re-a£t upon each other; themuriatic acid being liberated from its bafe bypart of the nitric acid, while another portionof the fame is decompofed, and its oxygenpaffes to the muriatic acid, thus converting itinto the oxymuriatic: hence the old chemiftswere in the habit of compofing an aqua regia,by diffolving fal ammoniac in nitrous acid, fordiflolving gold ; the occafional bad confequencesof which we have mentioned when treating ofthat metal.

The action of nitre and fal ammoniac infolution has not been inveftigated ; but if thelatter fait is added to nitre in fufion a partialdeflagration takes place, no doubt in confe-quence of the mutual decompofition of theammonia and nitric acid.

According to Gellert a boiling hot folutionof muriated ammonia is capable of diffolvingvegetable refin.

The action of fulphur and fa! ammoniac on2 N 2