Dr. Kane on the Compounds of Ammonia. 87 



Sulphate of zinc = 60.00 1 /^ • i 



^ > Gummy residue. 



«. Volatile matter = 20.29 J ■ • 



b. Volatile matter = 19.71 



Effloresced salt = 100.00 



From these results follow the formulae 



Transparent crystals = zwo.s03-|-2nh3-{-4ho 



Effloresced crystals := ZWO.SO34-2NH3-J-2HO 



Gummy mass = zno . SO3 -\- NH3 -|- ho 



Which gives by heat = zrao . SO3 



I shall, before proceeding further, return to the examination of the flocculent 

 substance which was deposited from the hot solution of the ammonia-sulphate. 

 It cannot be redissolved in water, which distinguishes it from the transparent 

 crystalline salt; when heated it fuses, and is decomposed with the escape of water 

 and ammonia, as is the case with the substance already described. It was ana- 

 lyzed as follows : 



5.033 of this flaky substance was heated until all escape of water or of 

 ammonia had ceased ; there remained 3.821 of sulphate of zinc, corresponding 

 to 75.92 per cent., and 



^1 = IWs' ^"^25.53-17.14 = 8.39, or nearly 9. 



Hence the formula is zno . so^ -f- nh, -]- ho. 



These flakes have therefore the same composition as the gummy mass 

 obtained by melting the crystalline salt, and this circumstance proves that the 

 gummy mass is really a definite chemical compound, which could not have been 

 so positively shown from the method by which it had been prepared. 



When the crystalline salt is kept for some time at a temperature of from 80° 

 to 100° F. it gradually falls down into a white powder, all traces of crystalline 

 structure having totally disappeared ; during this decomposition, water alone 

 escapes, as turmeric paper left on the surface of the powder is not at any period 

 affected. When this powder is heated to about 212°, it gives out water and am- 

 monia, which continues up to a certain point, but in order to finish the expulsion 

 of the water, the temperature must be raised until the mass has become fused ; 



VOL. XIX. I 



