DETERMINATION OF NITROGEN. 
143 
employ sufficient hydrate of the alkali, that the oxygen of 
water may combine with all the carbon of the organic matter. 
The residue should be white. According to the richness of 
the substance in carbon, and according to the temperature, 
there is likewise disengaged along with the ammonia, perma- 
nent gases, such as proto or deuto-carburetted hydrogen, hy- 
drogen, or rather a mixture of these gases, and in certain 
cases also liquid carbo-hydrogens, as benzine ; at least the 
oily drops which occasionally form have the odor of this sub- 
stance. 
To substances most rich in nitrogen, belong melamine, 
mellone, cyanogen and its combinations; but they all con- 
tain, in proportion to their carbon, as much, or even a little 
more carbon than is sufficient by its union with the oxygen of 
the water of the hydrate, to liberate enough hydrogen to com- 
bine with all the nitrogen to form ammonia. With some of 
these combinations, mellone, for example, of which the for- 
mula is C 6 N 8 , and melamine, C 6 N 12 H^, the decomposition 
is effected by the aid of a sufficient amount of hydrate, with- 
out producing a trace of permanent gas. The whole of the 
carbon is converted into carbonic acid, which remains in com- 
bination with the alkali, and all the nitrogen into ammonia, 
which is disengaged in its gaseous state. 
Our method, based as we have said, on this property of 
substances containing nitrogen, not at all, or only in small 
part, under the form of nitric acid, consists in collecting 
completely this ammonia by the aid of some acid, and to 
weigh it in the solid form, as hydrochlorate of ammonia and 
platinum. 
We use, for the accomplishment of this purpose, an appara- 
tus consisting of a tube of slightly fusible glass, from Om,433 
to O m ,487 in length (16 to 20 inches) such as is usually 
employed in ordinary combustions to determine carbon. 
This tube is drawn out at its end into a point, turned up 
obliquely and sealed, the other extremity is fused on the 
edges. It differs from the ordinary tube of combustion only 
in its diameter being much less, say about O m ,0067 (quarter 
