222 
MOM OF ESTIMATING NITROGEN, ETC. 
ART. XLV. — A NEW MODE OF ESTIMATING NITROGEN IN 
ORGANIC ANALYSIS. By Professor Bunsen, of Marlburg. 
The qualitative methods at present employed for the analy- 
sis of azotized bodies are admitted to be defective ; for it is 
impossible to employ these processes when the nitrogen and 
the carbon are in small proportions to each other. Professor 
Bunsen's process consists in introducing the substance to be 
analyzed after having mixed it with oxide of copper, into a 
glass tube. A few slips of metallic copper are then added, 
and the tube is fixed to Dobereiner's apparatus for producing 
hydrogen. This gas is conducted through it until all the at- 
mospheric air is expelled, the tube having a rotary motion 
given to it at the same time, in order to dislodge any air which 
might be retained between the particles of the oxide of cop- 
per. The tube is now hermetically sealed, and introduced 
into an iron vessel filled with gypsum. The gypsum must 
be still moist when the tube is introduced, in order that it 
may be firmly wedged. Thus prepared, it is introduced into 
the common oven, used for organic analysis, and surrounded 
with red hot coals. If the tube be of strong green glass it never 
bursts. When the combustion is completed, the tube is placed 
below a graduated glass receiver standing over mercury, and 
the point cut off. The gas which had a pressure of several 
atmospheres, now rushes into the jar. The carbonic acid is 
absorbed by a ball of hydrated potash, which is introduced in- 
to it, and the remaining gas must be nitrogen, for all the hy- 
drogen must have been converted into water by the oxygen 
of the oxide of copper. The results obtained by this method 
agree with theory to the second and often to the third decimal 
place. 
Ibid. 
