102 CONTRIBUTIOX TO THE STUDY OF 



of the products formed depend largely on the degree to which 

 the salt is heated, and hence the reaction cannot be represented 

 by a definite equation. 



PrejKcration of Hydroxylainine Nitrate. 



Hydroxylamine nitrate was prepared from the sulphate by 

 adding the required amount of barium nitrate. The solution 

 was set aside over night to allow the precipitated barium sulphate 

 to settle. The supernatant liquid was then decanted oft' through 

 a filter. On filtering a second time a perfectly clear solution was 

 obtained. This was evaporated to a small volume on the water 

 at a pressure of about half an atmosphere. The concentrated 

 solution thus obtained was then tested for barium and sulphate. 

 By adding carefully barium nitrate, or hydroxylamine sulphate, as 

 the case required, a solution was finally obtained which gave no 

 indication of the presence of either barium, or sulphate. This solu- 

 tion, on filtering, was then distilled in a small flask at a pressure 

 of about 20 mm. At this pressure both water and hydroxylamine 

 nitrate were found to distil over at a temperature below 50°. The 

 distillation was continued until only a few cc. of the solution 

 remained behind in the flask. A few cc. of the last portion of 

 the solution distilled over was separately collected and dried 

 over phosphorus pentoxide. The remainder of the distillate was 

 standardised by titration with iodine, and used in determining 

 the conductivity of the compound,— redistilled water being used 

 to make up the solution. 



On account of its explosive nature, a pure solution of the 

 salt was only obtained after repeated trials. I first endeavoured 

 to distill off the water by heating on the water bath at 100° and 

 pressure of half an atmosphere, with a view to purifying the 

 .salt by crystallising from absolute alcohol. At this temperature, 

 however, the salt exploded, leaving about 3cc. of water behind 

 in the flask. The solution was again prepared in the same way, 

 and, after being evaporated to a small bulk as before, was heated 

 on a water bath at a temperature of 80°. To hasten evapora- 



