98 E. DIVERS AND T. HAGA. 



The flasks were occasionally shaken, but as no incrustation of the 

 solution occurs in this case, agitation was less useful than in making 

 the potassium or ammonium salt. 



At the end of the time, the solution was showing slight effer- 

 vescence, indicative of decomposition going on in the salt. Hardly 

 any sulphite then remained, and nearly all of what sulphate had 

 formed or been present at starting was crystallised out by keeping the 

 solution for some time at a little below zero, and then removed. The 

 solution was quickly evaporated in a vacuum desiccator to a very 

 small volume, by which time it had yielded much of what proved to 

 be nitrososulphate, in opaque white crusts and deposits of minute hard 

 crystals, perfectly transparent under the microscope. Removed to the 

 porous tile and drained dry, the salt formed a crystalline powder, 

 tasting remarkably like common salt, slightly alkaline to litmus, and 

 free from sulphate and sulphite. It was weighed and then left for a 

 night in a desiccator, to see what it would lose in weight as moisture 

 and water of crystallisation. Next morning, it appeared to be un- 

 changed, and was placed on the balance-pan, between watch-glasses. 

 But it could not be weighed, because, it rapidly lost weight. Taken 

 from the balance and uncovered, it had not been a minute exposed to 

 the air before it began to have a nitrous odour, and then quickly grew 

 very hot and evolved much nitrous oxide mixed with nitric oxide, 

 which reddened in the air. The watch-glass which held the salt was 

 broken, and the wood of the table scorched, on which it rested. The 

 powdery solid residue was collected, with hardly any noticeable loss, 

 and weighed. 



This residue of the decomposed salt consisted of sulphate and 

 sulphite, and weighed, as collected, 5*645 grains, while the nitrososul- 

 phate, as placed in the desiccator, had weighed 7*595 grams. In 

 portions of the residue we determined its sodium by ignition with 



