DETERMINATION OF NITROGEN. 
151 
whole sal ammonia from the sponge obtained by the decom- 
position of pure hydrochlorate of ammonia and platinum. If 
this sponge be boiled with pure water, the decanted liquid 
commonly yields a precipitate with nitrate of silver. It is, 
therefore, necessary to subject the platinum sponge to fre- 
quent ebullitions in water, before dissolving it in aqua 
regia. 
In our opinion, it is both as simple in execution as certain 
in result, to reduce the weight of nitrogen from the hydro- 
chlorate of ammonia and platinum, as to transform this latter 
into platinum by calcination. If the nitrogen be weighed as 
hydrochlorate of ammonia and platinum, for 177 parts of the 
former, the balance must indicate 27SS of the latter ; while 
for the same quantity of nitrogen, we will have only 1233 
parts of metallic platinum. 
The errors of weight should therefore be twice as conside- 
rable with the hydrochlorate of ammonia and platinum, to 
effect the result as with platinum. The weight of hydrochlo- 
rate of ammonia and platinum remains constant under pro- 
longed dessication, at 100° C, and the filter does not alter at 
all, if the salt be perfectly washed ; but a trace of free acid 
remaining, it blackens and beeomes very friable, 
MM. Varrentrapp and Will have applied their process to 
the determination of nitrogen in numerous organic sub- 
stances, some rich and others poor in this element, which had 
been previously analysed by the best chemists. (Melamine, 
urea, uric acid, ox amide, cafeine^ asperagine, taurine, hip- 
puric acid, brucine, fyc.) The results which they have ob- 
tained, possess a strong resemblance with those of their pre- 
decessors, and prove in an incontestible manner the advan- 
tages of their process. " I do not doubt," says M. Liebig, 
" that it ivill replace very promptly and to the satisfaction 
of all analyses, the processes employed at the present time" 
A. G. V. 
Journ. de Pharm, and de Chim. 
