46 
SELECTED ARTICLES. 
3. Likewise, from another substance constituted of carbon, 
with oxygen and hydrogen in the proportion to form water, 
together with an excess of hydrogen, there will be formed 
equal volumes of carbonic and sulphurous acids, together with 
an excess of sulphurous acid, the volume of which being mul- 
tiplied by two, will give the volume of hydrogen which is in 
excess in the substance. 
4. In substances containing azote, the same phenomena 
Will take place as in the three preceeding cases, except that a 
quantity of azote will be set free, of which the relation with 
the sulphurous and carbonic acids will be constant throughout 
the whole operation. 
Hoping to have found a mode to fulfil the two conditions, 
which appeared essential to the exact analysis of organic sub- 
stances, in affording the means to verify the results, as well 
as to estimate, the body in the gaseous state, and with as 
little chance of error, as that each volume of sulphurous acid 
should double the volume of carbonic acid, there remains but 
to give the details of the operation itself, which is divided 
into two parts, the combustion of the organic matter by the 
sulphate of mercury, and the analysis of the gas resulting from 
the decomposition. 
To give an idea of the facility with which analysis, by 
this new method, may be performed, it will suffice to say, that 
with the assistance of one person to dry the receivers, and to 
procure the necessary charcoal, I can conduct two operations 
at the same time, and finish them in an hour and a half. As 
to the precision of the results, they are not less astonishing, 
for they are such, that when all the precautions pointed out 
are taken, we are more sure to obtain the same numbers 
in repeated experiments on the same substance, than we are 
in the analysis of air by the different methods applied to that 
fluid. 
Likewise, it renders us able to follow the changes in the 
dry distillation of organic matters, when by their nature they 
can afford hydrogenated products; which products, by an 
arrangement of the apparatus, so that they shall pass through a 
