_Uses._ Ammonia is employed in numerous processes in _chemistry_ and the _arts_; but chiefly in the form of ‘liquor of ammonia,’ ‘spirits of hartshorn,’ &c., and in combination, under the form of salts. In its pure or gaseous state it possesses little practical interest. =Ammonia, Solution of.= _Syn._ SOLUTION OF AMMONIA, LIQUOR AMMONIÆ, AMMONIUM HYDRATE, AMMONIA, Eng.; AMMONIAQUE LIQUIDE, DISSOLUTION D’AMMONIAQUE, ESPRIT DE SAL AMMONIAC, Fr.; ATZENDER AMMONIUM-LIQUOR, SALMIAK-GEIST, Ger.; LIQUORE DI AMMONIACO, Ital. Ammonia gas readily dissolves in water, one volume of water absorbing about 670 volumes of ammonia, much heat being liberated, and the solution increases greatly in volume. This solution is regarded in two very different lights; firstly and most generally as simply a solution of gaseous ammonia, a view rendered most probable by its general physical and by many chemical reactions; by a few, however, it is looked upon as a solution of ammonium hydrate. [Illustration] Prepared by distilling, in a tubular retort, equal parts of sal ammoniac, hydrated lime, or slaked lime and water, and passing the gas evolved through a set of Wolff’s bottles partially filled with water, as in the figure above. [Illustration: _A_, Cylindrical Iron Retort. _B_, Furnace for ditto. _C C C C_, Stoneware Receivers. _D D D D_, Connecting Pipes. _E F_, Waste Pipe and Receiver. _G_, Safety Tube. ] Commercially this article is prepared on the large scale, from a mixture of about equal parts of fresh-slaked lime and sal-ammoniac or sulphate of ammonia, which is heated in an iron cylinder or retort connected with a set of ‘refrigerators,’ the latter consisting of a row of stoneware bottles with double necks, containing water, and kept very cold. The general arrangement of the apparatus used in this manufacture is exhibited above, and with the accompanying references, will be easily understood. The ‘condensers,’ when in use, are surrounded with cloths (not shown in the _engr._) kept wet with very cold water, whilst constant current of cold air is commonly made to pass over them. The pipe (_D_) leading from the retort is also several feet long, and is advantageously passed through a wooden screen in order that the radiated heat of the retort and brickwork of the furnace may be intercepted as much as possible.