AMMONIUM, CHLORIDE OF 155 



bonic acid through it. A solution of chloride of ammonium or sulphate of ammonia 

 is obtained by filling tho condenser with diluted hydrochloric or sulphuric acid, and 

 passing the ammonia through it as it issues from the retort. 



Dr. Wilton Turner obtained a patent, March llth, 1844, for obtaining salts of am- 

 monia from guano. The following is his method of obtaining chloride of ammonium 

 in conjunction with cyanogen compounds : Tho guano is subjected to destructive 

 distillation in close vessels, at a low red heat during tho greater part of the opera- 

 tion ; but this temperature is increased towards the end. The products of distillation 

 are collected in a series of Woolfe's bottles, by means of which the gases evolved 

 during the operation may be made to pass two or three times through water, before 

 escaping into the air. These products consist of carbonate of ammonia, hydrocyanic 

 acid, and carbxiretted hydrogen, the first two of which are rapidly absorbed by tho 

 water, with the formation of a strong solution of cyanide of ammonium and carbonate 

 of ammonia. After the ammoniacal solution has been removed from the Woolfe's 

 apparatus, a solution of protochloride of iron is added to it, in such quantities as will 

 yield sufficient iron to convert tho latter into Prussian blue, which is formed on the 

 addition of hydrochloric acid in sufficient quantity to neutralise tho free ammonia ; 

 the precipitate thus formed is now allowed to subside, and is carefully separated from 

 the solution, and by being boiled with a solution of potash or soda, will yield tho 

 alkaline ferrocyanide, which is obtained by crystallising in the usual way. Tho 

 solution (after tho removal of the precipitate) should bo freed from any excess of iron 

 it may contain, by the careful addition of a fresh portion of the ammoniacal liquor, by 

 which means the oxide of iron will bo precipitated, and a neutral solution of ammonia 

 obtained. When the precipitated oxide and cyanide of iron have subsided, the solu- 

 tion of chloride of ammonium is drawn off by a syphon, and the sal-ammoniac ob- 

 tained from it by the usual processes ; the oxide of iron is added to the ammoniacal 

 solution next operated upon. 



If sulphate of iron and sulphuric acid are used, siilphato of ammonia is the am- 

 moniacal salt produced, the chemical changes and operations being similar to the above. 



Since the greater part of the nitrogen present in guano exists in tho state of ammo- 

 niacal salts, which are decomposed at a red heat, nearly tho whole of tho ammonia 

 which it is capable of yielding is obtained by this method ; still there cannot be a 

 doubt that the conversion of tho urea, iiric acid, and other nitrogenised organic bodies 

 into ammonia, is greatly facilitated by mixing the guano with lime before heating it, 

 as in Mr. Young's process. 



Manufacture of Sal- Ammoniac from Urine. The urea in tho urine of man and 

 other animals is extremely liable to undergo a fermentative decomposition in the 

 presence of the putrefiable nitrogenous matters always present in this excrement, by 

 which it is converted into carbonate of ammonia. 



By treating stale urine with hydrochloric acid, sal-ammoniac separates on evaporation. 



Properties. Chloride of ammonium (or sal-ammoniac) usually occurs in commerce, 

 in fibrous masses of the form of large hemispherical cakes, with a round hole in the 

 centre, having, in fact, the shape of the domes in which it has been sublimed. By 

 slowly evaporating its aqueous solution, the salt may occasionally be obtained in 

 cakes nearly an inch in height ; but it generally forms feathery crystals, which are 

 composed of rows of minute octahedra, attached by their extremities. Its specific 

 gravity is 1'45, and by heating it sublimes without undergoing fusion. It has a 

 sharp and acrid taste, and one part dissolves in 2'72 parts of water at 65 F., or in an 

 equal weight of water at 212 F. 



It is recognised by its being completely volatile on heating, giving a white curdy 

 precipitate of chloride of silver on the addition of nitrate of silver to its aqueous 

 solution, and by the copious evolution of ammonia on mixing it with lime, as well as 

 the production of the yellow precipitate of the double chloride of ammonium and 

 platinum NH'Cl, PtCP (2WH 4 C1. PtCl 4 ) on the addition of bichloride of platinum. 



Impurities. In the manufacture of chloride of ammonium, if tho purification of 

 the liquor be not effected before crystallising the salt, some traces of protochloride 

 of iron are generally present, and frequently a considerable proportion. Even when 

 tho salt is sublimed, the chloride of iron is volatilised together with the chloride of 

 ammonium, and appears to exist in the salt in the form of a double compound 

 (probably of Fed, NH 4 C1, analogous to the compound which chloride of ammo- 

 nium forms with zinc and tin) ; and this not only in the brown seams of tho cake, 

 but likewise in the colourless portion. This accounts for tho observation so often 

 made in the laboratory, that a solution of sal-ammoniac, which, when recently 

 prepared, was perfectly transparent and colourless, becomes gradually red from the 

 peroxidation of tho iron and its precipitation in tho form of sesquioxide. 



It is in consequence of the existence of tho iron in the state of this double salt, that 

 Wurtz found that chloride of ammonium containing iron in this form gave no indj. 



