Dr. Kane on the Compounds of Ammonia. 55 



Hence this acid, with constant boiling point, is composed of HcZ+ 16ho, and 

 its formula may properly be considered as 



h.c/-4-6ho -\- IOho. 

 corresponding to 



zncl-\-Qzno-\-\0-H.o. 

 the hydrated-oxychloride, which has been described. 



X. OF THE AMMONIA-SULPHATES OF ZINC. 



This salt was prepared by passing ammoniacal gas through a strong and hot 

 solution of sulphate of zinc, until the whole of the sub-sulphate precipitated had 

 been redissolved. The liquor, on cooling, deposited a flocculent mass, in semi- 

 crystalline grains resembling starch ; and if the liquor be evaporated, or kept 

 liot, the separation of this substance continues ; when, however, the solution is 

 allowed to cool, and then having been filtered, is left to spontaneous evaporation, 

 it remains clear ; and small, but perfectly distinct crystals are deposited, which 

 remain bright while moist, but effloresce, and become opaque almost immediately 

 on being dried and left in the open air. These two bodies contain alike, sulphuric 

 acid, oxide of zinc, ammonia, and water, but the quantity of the constituents is 

 not the same ; I shall therefore describe them separately, commencing with the 

 crystallized ammonia sulphate. 



When this salt is heated it gives water and ammonia, and there remains sul- 

 phate of zinc ; if the heat be very gently applied, all ammonia may be expelled, 

 and the residual sulphate of zinc will be quite pure ; but if the salt be suddenly 

 heated, a quantity of sulphate of ammonia is produced, and the sulphate of zinc 

 remaining is mixed with oxide. m 



As this salt, from the manner of its formation, must contain two equivalents 

 of ammonia to one of the sulphate of zinc, the analysis of it became very simple, 

 as it was to be directed specially to the examination of the quantity of water 

 which it might contain. 



In efflorescing this salt does not lose ammonia. To determine its composition, 

 3.701 of clear crystals, dried between folds of blotting-paper, were heated at first 

 very gently, but finally to ignition. On the first application of the heat the salt 

 fused, and emitting water and ammonia, left a perfectly white residue of sulphate 



