104 CONTltlBUTION TO THE STUDY OF 



flask, could be more readily noticed than by the manometer in 

 the air-pump. With the apparatus thus set up, the pressure 

 could be reduced to 15 mm. 



A thermometer was placd in the distilling flask so that the 

 bulb dipped in the salt to near the bottom of the flask. Heat 

 was applied to the flask with a free flame. At a pressure of 

 15-25 mm.., the principal part of the hydroxylamine distilled 

 over between 135"^ and 137 . This part of the distillation occu- 

 pied about 20 minutes. The hydroxjdamine distilled over as a 

 colorless liquid at the rate of about 2 drops a .second. A char- 

 acterisiic of the liquid was the small size of the drop.s. formed. 

 The temperature was then gradually raised to 160". Towards 

 the end of the operation, the temperature could be kept up to 

 this point with considerably less heat than was applied to the 

 flask at flrst. The distillation was stopped at the end of half an 

 hour. From 20grms. of the phosphate 5.6grms. of hj^droxjdam- 

 ine were obtained. 



The product left in the distilling flask consisted of a thick, 

 viscous, glass-like mass. This was found to consist of ortho- 

 phosphoric acid, pyrophosphoric acid and a small amount of 

 hydroxylamine which failed to distil over. 



The greater part of the hydroxylamine obtained was dissolved 

 in about 50cc. of water aad redistilled. At a pressure of 15-25 

 mm. both water and hydroxylamine were found to distil over at 

 a temperature of 33-35°. In this way a chemically pure solu- 

 tion of hydroxylamine was obtained, which was used to deter- 

 mine its conductivity. The solution was standardised by 

 titration with iodine. 



On distilling some hydroxylamine phosphate which was not 

 chemically pure, the hydroxylamine which distilled over was of 

 a reddish color. During the distillation, the temperature was 

 raised to 180°, and the pressure allowed to fall to 50 mm. with- 

 out explosion. Allowed to stand over night, the reddisli color 

 of the distillate was found to have entirely disappeared. The 



