NEW METHOD OF ANALYSIS, 43 
ART. VIII. — EXTRACT FROM A PAPER, ON ANEW METHOD 
OF ANALYSIS FOR THE ESTIMATION OF THE PRINCI- 
PLE CONSTITUENTS OF ORGANIC MATTERS. By M. 
Persoz, 
Having, in a preceding essay, laid down the principle that 
organic and inorganic combinations are formed by the same 
laws, it remains for me to verify this, by experimentally 
studying the proximate composition of organic bodies. As the 
study of the elementary composition necessarily precedes that 
of the proximate, there presents a great difficulty in the choice 
between the different results often afforded by the same sub- 
stance. Before being discouraged by this, it is necessary to 
examine whether the methods used are capable of being per- 
fected; and, moreover, what bearing they have upon the 
general principles of analysis, at the head of which the fol- 
lowing should be placed: 
In all kinds of analysis, to have sure means at our disposal 
to verify directly and indirectly the results, and never to 
permit ourselves to calculate a result by a difference. 
Likewise, this: 
To estimate the quantity as far as possible while in the 
gaseous state, and likewise, if we can, to transform a gaseous 
body into a definite gaseous combination, in which the sub- 
stance we wish to estimate shall occupy a more considerable 
volume. 
If we are content, as some have been, to decompose a sub- 
stance by the oxide of copper, to convert it into water and 
carbonic acid, and having weighed these two compounds to 
ascertain, on the one part, the quantity of hydrogen, and on 
the other, the quantity of carbon, to deduct the sum from the 
weight of the matter employed, for the purpose of obtaining 
by difference the quantity of oxygen it is supposed to contain, 
we are really only exact as to the quantity of carbon; for 
there is nothing to prove that a greater or less quantity of 
hydrogen does not exist in the substance in the form of water, 
