HYDKOXYLAMIXE AXD ITS SALTS. ROSS. 97 



after adding- a few drops of sulphuric acid. Hydrolysis was found 

 to take place quite rapidly accompanied by a marked rise in tem- 

 perature. Care had to be taken not to heat the solution too 

 strongly at first, as it had a tendency to froth over. Effervescence 

 was seen to cease in a short time, and the liquid was then heated 

 to 90°. To complete the second stage in the hydrolysis, it was 

 found necessary to keep the solution at this temperature for 

 about 55 hours. When hydrolysis was completed, was deter- 

 mined by adding to a small portion of the liquid, an excess of 

 barium chloride. If on filtering and treating the filtrate with a few 

 crystals of potassium chlorate, no cloudiness took place on boil- 

 ing, then the oxyamidosulphonate was known to be wholly 

 converted to sulphate. The liquid was heated in porcelain jars 

 instead of glass vessels on account of their being less liable to 

 break, and also on account of the ease with which the solution 

 could be heated to 90''-95° without bumping. 



The excess of acid in solution was neutralized by adding the 

 required amount of sodium carbonate. This amount was calcu- 

 lated by titrating a small portion of the solution with a portion 

 of the prepared sodium carbonate solution — methyl orange being 

 used as an indicator. The neutral solution was then evaporated 

 down until it weighed about eleven times the weight of the 

 sodium nitrite taken. On setting aside to cool, a large amount 

 of sodium sulphate crystals separated out. Successive crops of 

 crystals were then removed until no further separation of 

 crystals would take place from the mother liquor. The last 

 evaporation was brought about at reduced pressure to prevent 

 decomposition. The crop of crystals containing the largest pro- 

 portion of hydroxylamine was then taken, dissolved in water, 

 and successive small portions of crystals removed b}^ evaporating 

 ofl" the required amount of water at reduced pressure. This was 

 kept up until the whole of the solution was crystallized. No 

 crop of cr3'stals, however, was found to be entirely free from 

 sodium. The crop of crystals richest in hydroxylamine was 

 then taken and recr^'stallised a great number of times. Although 



