AMMON I AC AL SALTS.

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Carbonate of Ammonia.

Carbonate of ammonia (NH + 0,C0 2 ), occurs in commerce as a white crys-talline mass smelling strongly of ammonia and soluble in water. It has buta small number of applications in dyeing, being chiefly employed to brightencolours, especially magenta, to form a soap with the grease of certain fibres, &c.

Sal-Ammoniac.

Sal-ammoniac, or chloride of ammonium, NH 4 C1, forms a colourlesscrystalline mass, the whole of which, when pure, is volatile by heat. Thecrystals not unfrequently contain salts of iron, contradted from the vesselsin which the sal-ammoniac has been prepared. An aqueous solution of sal-ammoniac, in which nitrate of potash has been boiled, should not, aftercooling, exhibit a red colouration on the addition of sulphocyanide ofpotassium. Sal-ammoniac is employed in the preparation of certain baths,as well as in the precipitation of alumina from aluminate of soda. It modifiesthe adtion of metallic salts upon organic colours, and is extensively used alongwith compounds of copper. It serves in the preparation of pink-salt.

Nitrate of Ammonia.

Nitrate of ammonia possesses the property, by means of the ammonia itcontains, of depositing from the acetate of alumina baths the mordant in abasic condition, and by the nitric acid it contains to oxidise the protoxide ofiron of the iron-bath to a higher oxide. Better results can be obtained inprinting catechu shades and garancine colours, with a bath of nitrate ofammonia (i° to 3 0 B.) than with chlorate of potash.