ARGON, A NEW CONSTITUENT OI'' THE ATMOSPHERE. 3 



improvement, and it was thought desirable to try wlietlier the gas prepared from 

 hypochlorite and urea would be pure on simple desiccation. A filling on June 

 25th gave as the weight 2.3343, showing an excess of 36 mg.,as compared with other 

 chemical nitrogen, and of about 25 mg. as compared with atmospheric nitrogen. 

 A test with alkaline pyrogallate appeared to pi-ove the absence from this gas of 

 free oxygen, and only a trace of carbon could be detected when considerable 

 quantity of the gas was passed over red-hot cupric oxide into a solution of baryta. 



Although the results relating to urea-nitrogen are interesting for comparison 

 with that obtained from other nitrogen compounds, the original object was not 

 attained on account of the necessity of retaining the treatment with hot metals. 

 We have found, howevei-, that nitrogen from ammonium nitrite may be prepared 

 without the employment of hot tubes, whose weight agrees with that above cpioted. 

 It is true that the gas smells slightly of ammonia, easily I'einovable by sulphuric 

 acid, and ap[)arently also of oxides of nitrogen. The solution of [)otassium nitrite 

 and aiiimonium chloi'ide was heated in a water bath, of which the temperature rose 

 to the boiling point only towards the close of operations. In the earlier stages the 

 temperature rerpiired cai-eful watching in oi-der to prevent the decomposition taking 

 place too i-apidly. The gas was washed with sulphuric acid, and after passing a Ness- 

 ler test, was finally treated with potash and phosphoric anh^'dride in the usual way. 



The following results have been obtained : 



July 4th 2.2983 



" 9th 2. 2989 



" 13th 2.2990 



Mean 2.2987 



It will be seen that in spite of the slight nitrous smell there is no a[)preci- 

 able difference in the densities of gas prepared from ammonium nitrite with and 

 without the treatment by hot metals. The result is interesting as showing that 

 the agreement of numbers obtained for chemical nitiogen does not depend upon 

 the use of a I'ed heat in the process of purification. 



The five results obtained in more or less distinct ways for chemical nitrogen 

 stand thus : 



From nitric oxide 2.3001 



From nitrous oxide 2.2990 



From ammonium nitrite purified at a red heat 2.2987 



From urea. . . 2.2985 



From ammonium nitrite purified in the cold 2.2987 



Mean 2.2990 



