AMMONIA.— Chloride of Ammonium.

189

cooled they were taken out, broken, and the cake ofsalt abstracted, and in this form was exported toEurope . On breaking the bottles, a nucleus of thesalt was found surrounded by a fixed pulverulentsubstance, which was taken out and mixed with freshportions of the soot in the succeeding operation.Considerable quantities of the salt were evidentlylost by this mode of preparation.

In India ammonium chloride was manufactured inmuch larger quantities than in Egypt . The cakes fromthe subliming vessels had the form of a sugar loaf,and weighed about 15 lbs. These loaves were com-posed of three distinct layers; the upper of each wasimpure, and was generally cut off. Egyptian andIndian sal-ammoniac was a dull, spongy, and greyishmass, considerably inferior to the sal-ammoniac nowmade; nevertheless, on account of its scarcity, itcommanded a price more than six times that of pureammonium chloride at the present time.

Before the introduction of gas-lighting, the am-monium chloride made in Europe was obtained fromoffal, or from the refuse cake of oil presses, either byallowing the ammoniacal compound to undergo putre-factive fermentation, or by submitting it at once todestructive distillation; the latter course was adoptedin Germany . In this country the soot deposited frompit coal was at one time employed to yield thesalt. The distillation of pit coal affords considerablequantities.

At present ammonium chloride is extensively pro-duced as a bye product in the manufacture of bone

charcoal. The bones are distilled in iron retorts.The accompanying engravings may be taken as typicalof the arrangements commonly made. Figs. 8, 9,

and 10 represent a furnace for distilling bones, andobtaining the ammoniacal compounds and the oilfrom them.

Fig. 8 is a longitudinal vertical section of theretort, A a, for holding the bones, showing its position

Fig. 9.

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in the dome of brick which encloses the fire, b. Theflue, after passing round the retort, is shown toadvance to the front of the furnace, as at D, before itreturns by the arch, E, and enters the chimney, J, atthe back. The pipe, G, emerging from the far end

of the retort, enters the cylinder, IT, Fig. 10, intowhich it conducts all the eliminated products of thedistillation.

Fig. 9 is a vertical section of the series of retortsand furnaces, made at right angles with Fig. 8, and