AMMONITE HYDROCHLORAS.

179

into sulphate, either by the addition of sulphuric acid, or by digestionon ground plaster of Paris (sulphate of lime). In the first case carbonicacid is evolved, in the latter we get carbonate of lime formed, fromwhich the solution of sulphate of ammonia is separated by filtering. Byevaporation, the solution yields brown crystals of sulphate of ammonia.This is sublimed with common salt, by which we obtain sulphate of sodaand hydrochlorate of ammonia. Every equivalent or 57 parts of sulphateof ammonia re-act on one equivalent or 60 parts of chloride of sodium,and with one equivalent or 9 parts of water produce one equivalent or 54parts of hydrochlorate of ammonia, and one equivalent or 72 parts ofsulphate of soda.

INGREDIENTS USED.

RESULTS.

1 eq. Hydroclil te . Ammonia . 54

^ i eq. Sulphate Soda

72

-l

1 eq. Sulph te . Amm. 5 7 | j e^SuIph^ 4 01 eq. Water . . . 9^^ 8

1 eq.Clil de .Sodium 60 ) } e< l' Chlorine. 36

(b.) From coals. —In the distillation of coal as practised at the gas-works, the volatile matters are conveyed to a condensing vessel or refri-geratory, in which are deposited tar and an ammoniaeal liquor whichcontains several salts of ammonia—as the sulphate, carbonate, hydrocya-Fig. 45. nate, and hydrosulphate. On the

addition of sulphuric acid the car-bonate, hydrocyanate, and hydro-sulphate are decomposed, and byevaporation brown crystals of sul-phate of ammonia are obtained.This salt is mixed with chloride ofsodium, and heated in an iron potlined with clay, to which a leadenSublimation of Hydrochlorate of Ammonia, headhaving an open cylindrical tubeis adapted (fig. 45). The hydrochlorate of ammonia is sublimed into thehead of the apparatus. In the clay removed from the pots after the opera-tion, small but perfect and beautiful crystals of the bisulphuret of iron aresometimes found. They are formed during the process. In some casesthe gas liquor is saturated with hydrochloric acid, and the brown crystalsof hydrochlorate obtained by evaporation are purified by sublimation.The above is a sketch of the process which I saw in operation a fewyears since at the Westminster GasWorks. At the present time the gasliquor is sold to sal ammoniac manufacturers, who reside in the outskirtsof the metropolis.

Properties.— Hydrochlorate of ammonia usually occurs in commercein the form of large hemispherical cakes, which are translucent, and byexposure to the atmosphere become slightly moist. By solution or su-blimation it may be obtained in regular octahedral, or cubic, or plumosecrystals. Its sp. gr. is l - 450. Its taste is saline and acrid; it has noodour. "When heated, it sublimes without undergoing fusion or decom-position. It is soluble in about 3 parts of cold and 1 of boiling water:cold being produced during the solution. It dissolves in alcohol.

Characteristics. —It maybe recognized by the following characters:it is white and volatile ; and if heated on the point of a knife by theflame of a candle, it readily sublimes. Mixed with caustic potash, orquicklime, it evolves ammoniaeal gas, which is known by its odour, itsaction on turmeric paper, and its fuming with the vapour of hydrochloric