206 E. DIVERS AND M. OGAWA : PRODUCTS OF HEATING 



ferric chloride given by u thiosulphate. Analysis of the subli- 

 mate and of that part of the salt which remained mixed with 

 the sulphur when the progress of the decomposition was arrest- 

 ed after only half of it had been decomposed, gave results that 

 showed the former to be essentially anhydrous normal sulphite, 

 and the latter unchanged thiosulphate : — 



The main decomposition of the thiosulphate is in full agree- 

 ment wit1i the relation of thiosulphates to sulphites. Very in- 

 teresting is the production of a little ammonia and hydrogen 

 sulphide, in connection with the relation of trithionate to thiosul- 

 phate as its thio-anhydride (Spring) :— 2(Nfi,)2S203=2NH3 + 

 SH2 + (NH4)2S30fi. When ammonium thiosulphate is rapidly and 

 more strongly heated, ammonia is lost and sulphur sublimes; then 

 as a matter of course and of no significance, thiosulphate and 

 even trithionate are produced on adding water to the mixed 

 sublimates. 



Ammonium pyrosulphiie. — We did not get this exceedingly 

 deliquescent salt into the tube ready for heating before it had 

 condensed some moisture, and to this we attribute part of the results 

 obtained. Change went on slowly in the salt at 130° and some- 

 what faster at 150°. At first there was little else than a slight but 

 steady evolution of sulphur dioxide, and this continued though very 

 feebly, to the end and while a sublimate forming. The sublimate 

 was pyrosulphite in one experiment ; in another, it was this salt 

 mixed with a very little anhydrous sulphite. But there was a 



