A NEW CONSTITUENT OF THE ATMOSPHERE. 189 
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, 
however, that nitrogen from ammonium nitrite may be prepared without the employ- 
ment of hot tubes, whose weight agrees with that above quoted. It is true that the 
gas smells slightly of ammonia, easily removable by sulphuric acid, and apparently 
also of oxides of nitrogen. The solution of potassium nitrite and ammonium chloride 
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 required 
careful watching in order to prevent the decomposition taking place too rapidly. The 
gas was washed with sulphuric acid, and after passing a Nessler test, was finally 
treated with potash and phosphoric anhydride in the usual way. The following results 
have been obtained :— 

Dialysis. Saree niin amr 2p2983 
5 9 22989 
og he} 2°2990 
Wieam-, 4 -5-=, Bx2oer 
It will be seen that in spite of the slight nitrous smell there is no appreciable differ- 
ence 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 nitrogen does not depend upon the use of a red 
heat in the process of purification. 
The five results obtained in more or less distinct ways for chemical nitrogen stand 
thus :— 

IBrOmMUEnIETIChOXIGe mal UE 4) re cee Gy elite hale bras piseal nem, ie eS) (il 
TOMI CLOUSNOMIC CII ese Coke Chia en rece hee ever eet Co. 9\() 
From ammonium nitrite purified atared heat . . . . 2°2987 
TOMEI C AEP aarEnESS esta Fee for Seren nee Rakes Mme ON) 
From ammonium nitrite purified inthe cold. . . . . 2:2987 
Meant ii ts, sees ea 2 2990 
These numbers, as well as those above quoted for “atmospheric nitrogen,” are subject 
to a correction (additive)* of -0006 for the shrinkage of the globe when exhausted.t If 
they are then multiplied in the ratio of 2°3108 :1°2572, they will express the weights 
of the gas in grams. per litre. Thus, as regards the mean numbers, we find as the 
weight per litre under standard conditions of chemical nitrogen 1°2511, that of 
atmospheric nitrogen being 1°2572. 
[* In the Abstract of this paper (‘ Proc. Roy. Soc.,’ vol. 57, p. 265) the correction of ‘0006 was 
erroneously treated as a deduction.—April, 1895. 
+ Rayueien, “ On the Densities of the Principal Gases,” ‘ Proc. Roy. Soe.,’ vol. 53, p. 184, 1893. 
