1914-15.] Pelouze’s Method for determining Nitrates. 169 
placed in the flask and also 5 c.c. of strong sulphuric acid, the mixture 
being then cooled. The flask was then attaclied to the carbonic an- 
hydride apparatus : filled with that gas : detached from the condenser and 
a measured volume of the nitrate solution added : a stream of carbonic 
anhydride again passed, and its passage continued during the experiment. 
As soon as it was judged that all the air in the flask had been displaced, 
the mixture in the flask was boiled for a certain time, cooled, diluted, 
transferred to a porcelain dish, and titrated with N/10 permanganate. 
The following results were obtained : — 
Period of 
boiling. 
Nitric N 
(taken). 
Nitric N 
(found). 
Difference. 
15 inin.-^ 
0-0280 
0-0280 
0-0000 
30 „ 
0-0280 
0-0279 
0-0001 
60 „ 
0-0280 
0-0274 
0-0006 
60 „ 
00252 
0-0249 
0-0003 
15 „ t 
0-0070 
0-0069 
0-0001 
15 „ 
0-0056 
0-0056 
0-0000 
It is suggested that this method might be employed for determining 
nitrates in drinking waters, the amount varying, according to some books, 
from 0*05 parts nitric nitrogen per 100,000 to an average of 5*0 in 
shallow well waters and 0*5 in deep well waters. Of course, in such cases 
100 to 500 c.c. of the water would have in the first place to be evaporated 
to small bulk. I 
* With KNO3 solution 1 c.c. = 0’014 N. 
t „ „ -0-0014 N. 
I A student altogether without experience of the method was asked to test it, and was 
given the necessary apparatus and reagents. The results obtained were as follows 
Given. Obtained. 
(1) Nitric nitrogen 0*0070 0 0070 
(2) „ „ 0-0070 0-0070 
{Issued separately June 24, 1915.) 
