1819.] Sur ’'Identité des Forces Chimiques et Electriques, 375 
Cuapr. I].—Of the Chemical Forces. 
The most astonishing of all the forces which produce the 
chemical effects is fire. The kind of combustion which has 
been hitherto almost exclusively studied by chemists, is that 
which results from the union of a burning body with oxygen. 
To express the cause of this phenomenon, we say that the com- 
bustible body has an affinity for oxygen; and that oxygen has 
an affinity for the burning body. After a body has burned for 
a certain time, it loses its faculty of burning any more in the 
same circumstances. This change is expressed by saying, that 
the body is saturated with oxygen. This phrase means merely 
that the attraction of the combustible substance for oxygen has 
become so weak that it is no longer capable of overcoming the 
forces opposed to it. But im more favourable circumstances, 
the combustion of the same body may proceed further. Even in 
this case, it would find a limit ; and the same thing would take 
lace in every supposed situation, till at last the property of 
faite in the body would be completely destroyed. From this 
we learn, that the attraction of the burning body for oxygen is 
weakened or even annihilated by an activity which exists in the 
oxygen. Inthe same way the attraction of the oxygen for the 
burning body is destroyed by an activity residing in the burning 
body. Thus these two forces (that in the oxygen and that in 
the burning body) have the property of mutually neutralizing each 
other. In many cases the neutralization is so complete that we 
can neither detect in the compound the property of burning, nor 
that of supporting combustion. Now in physics, those forces 
which mutually destroy each other are called opposite forces. 
The same mode of speaking ought to be introduced into chemis- 
try : the attraction of combustible bodies for supporters is not the 
only comnion property which they possess; there are several 
others which disappear and reappear along with this attraction. 
Thus the property of acquiring electricity by contact with con- 
ductors, that of uniting with other combustibles, and that of 
acting strongly upon light, may be mentioned as instances. If 
we were to explain these phenomena by saying that they depend 
upon the attraction of the burning body for oxygen, we should 
not express every thing which results from the nature of a 
combustible body. We shall, therefore, call this property com- 
bustibiliity, and the activity which distinguishes it the force of 
combustibility. For the same reason the attraction of oxygen 
for combustible bodies, and all similar attractions, may be called 
the burning ‘force (force comburente). 
Combustion then is produced by the mutual attraction which 
exists between the burning force and the force of combustibility, 
forces which have the property of destroying each other, and 
which for that reason ought to be called opposite forces. 
The combination of bodies with oxygen is not only accompa- 
