3. That of Mr Laming (Patent dated Aug., 1852), in which a stream of SULPHUROUS ACID GAS is transmitted through the liquor containing the ammonia, either in the free state or as carbonate, by which SULPHITE OF AMMONIA is formed. This salt he oxidises, and thus converts into the SULPHATE OF AMMONIA, by agitation and free exposure to the air. Sulphate of ammonia, like the hydrochlorate, may also be obtained by saturating stale urine with the acid, and subsequent evaporation and crystallisation. See AMMONIA; AMMONIA, CARBONATES OF; AMMONIUM, CHLORIDE OF, and MANURES, &c. =Ammonium, Sulphide of (neutral).= (NH_{4})_{2}S. _Prep._ Saturate strong solution of ammonia with pure sulphuretted hydrogen gas; then add a second portion of solution of ammonia, equal to that first used, and preserve it in a well-stoppered bottle. =Ammonium, Sulphydrate of.= NH_{4}HS. _Syn._ SULPHIDE OF AMMONIUM, HYDROSULPHIDE OF AMMONIUM, HYDROSULPHATE OF AMMONIA. _Prep._ By passing sulphuretted hydrogen gas, to saturation, through a mixture composed of strong solution of ammonia, 1 part, and distilled water, 4 parts. _Props._ Prepared as above, it has a very fœtid odour. When pure it is wholly volatilised by heat, and does not disturb a solution of sulphate of magnesium. Mineral acids decompose it, with the evolution of sulphuretted hydrogen. By keeping, it decomposes and acquires a yellow colour. This yellow coloration does not, however, render it unfit for use as a reagent; but it must be borne in mind that it will now deposit sulphur when mixed with acids. In this state it proves valuable as a reagent to detect hydrocyanic acid, and as a solvent to separate metallic sulphides thrown down by sulphuretted hydrogen. _Uses, &c._ It is principally employed by chemists as a reagent to precipitate metals, to separate metallic sulphides, &c.; and by the perfumers as a mordant in dyeing hair. In _medicine_ it has been used by Cruickshank, Rollo, and others, to check the morbid appetite, and to increase the action of the stomach and general tone of the system in diabetes mellitus. It has also been used by Brauw, Gruithuisen, and others, in old pulmonary and vesical catarrhs. It is a powerful sedative, lessening the action of the circulatory system, causing nausea, vomiting, vertigo, drowsiness, &c.——_Dose_, 3 to 6 drops, three or four times daily, mixed with pure water, and instantly swallowed. In large doses it is poisonous. _Ant._ Very dilute solution of chlorine, or of chloride of lime or soda, followed by a powerful emetic, or the stomach-pump. When the vapour has been respired, free exposure to fresh air, with the head a little elevated, and copious affusions of cold water, with moderate draughts of brandy-and-water, and the use of the smelling-bottle (ammoniacal) should be adopted. If need be, artificial respiration should be attempted, and the air around the patient should be slightly impregnated with the fumes of chlorine or chloride of lime.