Ammonium, Sesquicarbonate of

Probably 2NH 4 HCO 3 + NH 4 NH 2 CO 3 , i. e. a mixture or compound of bicarbonate of ammonium and carbamate of ammonium. Syn. ( Carbonate of ammonia , Ammoniæ carbon as . B. P.). Carbonate d’ammonia que , Fr.; Kohl ens aures ammoniak , Ger. It is prepared on a very large scale commercially as follows:—Sal ammoniac or sulphate of ammonia, and chalk, equal parts, both dry and in powder, are mixed as before, and sublimed from a series of iron retorts or iron pots, into a well-cooled and capacious receiver lined with lead or earthenware; or, more generally, into such a receiver connected, by iron or lead pipes, with a second and similar one containing a stratum of water, to absorb the free ammonia evolved during the proce . The so-called “Volcanic Ammonia” is evolved during the manufacture of borax, from carbonate of soda and boracic acid. It is largely used in pharmacy. Prop. The carbonate of ammonia, of commerce, usually occurs in the form of white, fibrous, translucent, or semi-translucent cakes, generally about two inches thick. It is le volatile and pungent than the neutral carbonate; soluble in 4 parts of water at 55° Fahr., 3·3 parts at 62°, 2·5 parts at 96°, and 2 parts at 120°; boiling water and alcohol decompose it, with the evolution of carbonic acid gas and ammonia; by age or exposure to air, the surface a umes an opaque white colour, from its carbonate flying off, and the remaining bicarbonate being le volatile. Unlike the carbonate, it can neither be resublimed nor digested or distilled with either alcohol or water, without suffering decomposition. Sp. gr. 0·966. The exact composition of this salt varies, according to its method of preparation. Uses, . It is commonly employed by bakers to give lightne to their fancy goods, and to make extemporaneous bread and pastry; by the chemist and pharmaceutist, for the preparation of other salts of ammonia, and in analysis, . In medicine it is used as a stimulant, antispasmodic, antacid, and diaphoretic, in acidity of the stomach, dyspeptic affections, gout, scrofula, hysteria, lowne of spirits, epilepsy, .; and in the convulsions attending dentition. It has been recently recommended, by Dr Barlow, in diabetes. It is also employed to make effervescing draughts; and externally as a counter-irritant and stimulant. Its use as a nasal stimulant in headaches, fainting, ., is well known. In large doses it is emetic; in exce ive doses poisonous. Its long-continued use, in quantity, is often productive of very serious consequences—slow fever, debility, emaciation, scurvy, lo of teeth, hæmorrhage, general cachexy, and even death. The antidote and restorative treatment are, the free use of lemon-juice, wine or malt-liquors, new milk, and antiscorbutic vegetables, with a generous diet, of which the red meats form a large proportion.— Dose. As a stimulant or diaphoretic, 5 to 15 gr., di olved in cold water; as an emetic, 20 to 30 gr., in tepid water, repeated if nece ary; as an effervescing saline draught, 15 to 30 gr. A few grains (8 or 10) di olved in a tumbler of cold water is an excellent ‘refresher’ in lowne of spirits, or after fatigue; and is highly esteemed by drunkards; being, in each case, preferable to ‘spirit of sal volatile,’— Doses for Animals. Horse : 1 to 2 drachms. Cattle : 2 to 4 drachms. Sheep : 20 grains to 1 drachm. Pig : 20 grains to 1 drachm. Dog : 3 to 10 grains; in bolus, pill, or cold gruel. Concluding remarks, Patents, . In extension of the above it may be added that, on the large scale, the distillation is usually carried on in cast-iron retorts, similar in size, shape, and character to those employed in the manufacture of coal-gas, and of which five, or more, are commonly set horizontally in the same furnace. (See engr. ) Each retort has its mouth ( a ), through which the ‘charge’ is introduced, closed with a movable door, which is securely fastened in its place, in the manner shown in the engr.; and is furnished, at the upper part of its further end, with an iron pipe ( c ), to carry off the evolved vapours to the condenser or receiver. The latter consists of two large square wooden chambers ( B, C ), lined with lead, and either fitted with movable covers, secured by water-joints, or with doors in the side, to permit of the easy removal of the sublimed salt. The first receiver communicates with the second by means of a large lead tube ( d ) near its centre, and by another tube ( d′ ), somewhat smaller, and nearer the bottom, but above the surface of the stratum of water in the second receiver, before alluded to. These chambers have also a lead pipe ( e, e ), stopped during the proce with a plug or cock of lead, to allow of the liquid product of the distillation, ., to be drawn off, or run into another receiver or cistern, at will. Both chambers are placed on strong wooden supports, or scaffolding, to bring them on a level with the retorts. When the impure sulphate or other ammonia-salt is used in the manufacture of the sesquicarbonate (which is generally the case), the resulting salt being impure and discoloured, is resublimed in iron pots ( f, f, f ), furnished with movable leaden heads, which are kept cool by a current of air pa ing over them; a little water being introduced into the subliming pots to render the product translucent. The heat is applied either by means of a flue pa ing from the retort-furnace ( A, b ), or by a water bath heated in the same manner; the latter being the preferable method, as the temperature should not be greater than about 200° Fahr., and need not exceed 150° to 155°. These pots are arranged in sets, as shown at D in the engraving. IMG:596405606043057898_i143.png: The charge of a retort usually consists of about 70 to 72 lbs. of sulphate of ammonia or 57 to 58 lbs. of the hydro chlorate to 1 cwt. of chalk; or in these proportions. The product is about 40 lbs. of the crude salt, which, by careful resublimation, yields about 39 lbs. of marketable carbonate of ammonia. Carbonate of ammonia, like the chloride and sulphate, is now scarcely ever prepared on the small scale, that of commerce being not only cheaper, but sufficiently pure for all the purposes of medicine and the arts.