304 Researches upon the Heat develeped 
And as we have seen that the heat manifested in the 
combustion of one pound of hydrogen which is in the 
8°3333 pounds of steam which are the products of this 
combustion, is sufficient for raising the temperature of this 
Steam to that of 8750° F. itis evident that if this same 
quantity of heat is divided among 25°2113 pounds of steam, 
the temperature of this steam could not be higher than 
2891° F. 
This is therefore the highest temperature which we ought 
to find in the midst of a strong fire fed by the atmospheric 
air in which the combustible burnt is pure hydrogen. 
- As this temperature is much lower than that which we 
can excite by combustion, even without employing pure 
hydrogen or pure oxygen, the result of this calculation fur- 
nishes a demonstrative proof that the capacity for heat of 
steam, or rather that of azote, is diminished when its tempe- 
rature is increased. In all probability, the capacities of both, 
and generally of all elastic fluids, are diminished when their 
temperature is increased. ; 
We shall now see what is the highest temperature which 
it would be possible to attain by burning charcoal, and by 
blowing the fire with pure oxygen gas. 6.9 
According to Crawford, one pound of charcoal gives heat 
sufficient in its combustion to raise the temperature of 
57°608 pourfds of water 180° F., or to raise the temperature 
of 9369°44 pounds of water 1 degree. 
Now as one pound of charcoal is united to 2°5714 
pounds of oxygen in burning, and forms with it 3°57 14 
pounds of carbonic acid, the heat which is found in 
3°5714 pounds of carbonic acid at the instant of its forma- 
tzon would be sufficient to raise the temperature of 9369°44 
pounds of water 1 degree: consequently the heat which is 
in one pound of this acid at the moment of its formation 
would be sufficient to raise the temperature of 3643°6 pounds 
of water | degree, | } 
Here we have the quantily of heat which exists in the 
carbonic acid at the instant of its formation. In order to 
know what is the intensity which it would indicate if we 
could measure it at this moment, by means of a thermo- 
meter, it would be necessary to know precisely the specific 
heat of the carbonic acid. If, with Crawford, we take it 
at 1°0459 (that of water being taken =1), we shall have 
3811° F. for the measure of the intensity of the heat which 
exists in the carbonic acid at the moment of its formation, 
and consequently for the intensity of the greatest fire made 
with charcoal (without mixture of hydrogen) even in the 
case where the fire is fed by pure oxygen. It 
