DETERMINATION OF NIT&OGEN. 147 
ration, unites with the azote to form ammonia which escapes 
in a gaseous state. There is developed at the same time, ac- 
cording to the quantity of carbon in the organic matter, pure 
hydrogen gas, or carburetted hydrogen, which is not absorb* 
ed by the acid. 
Attention should be paid that the combustion proceed 
promptly, and that the gas is disengaged without interruption. 
There is no danger of less of ammonia, the absorption is so 
complete and so rapid that there is more fear of the rise of 
the liquid. When the disengagement of gas experiences a 
short interruption the liquor rises in the bulb a, and when 
the fire is carelessly managed, so rapidly that part passes 
through the tube d into the tube of combustion ; in which case 
the experiment is a failure. 
There are but few substances which contain nitrogen suffi- 
cient to render the oxidation and conversion of all the carbon 
into carbonic acid necessary to set free sufficient hydrogen to 
form ammonia with all the nitrogen. But we know of 
only one organic matter containing nitrogen, not in the 
form of nitric acid, which does not contain at least enough 
carbon. In this number is found, as already stated, mellone, 
mellamine, &c; these substances, as well as sulpho-cyanogen, 
yield perfectly exact results, if we observe in their analysis the 
following precautions: 
When the greater part of the air of the apparatus is expel- 
led by the first application of heat, nearly pure ammonia is 
disengaged ; this is then absorbed with so much force by the 
acid, that however large the bulb of the absorption apparatus 
may be, a rapid rise of the hydrochloric acid, even to the 
tube of combustion, is almost inevitable. It is very easy to 
obviate this inconvenience, by incorporating with the mix- 
ture of theorganic matter, containing nitrogen with soda and 
lime, an organic substance not containing nitrogen, such as 
sugar. These bodies give, during their decomposition by the 
hydrate of the alkali, permanent gases, which, by diluting 
VOL. VIII. NO. II. 19 
