448 On the two great powers, [Supr, 
not filling more space than before. Now, it is clear, each presses 
on the water and each bears one-half of the pressure of 30 pounds, so 
that the elastic force introduced with the oxygen gas has enabled the 
nitrogen to double its bulk under the pressure of the air; and has 
done nomore. If instead of adding the oxygen gas, heat had been add- 
ed to the nitrogen until its bulk had been doubled by expansion, it is 
manifest the 480° which effected this would have introduced as great 
an effective dilating power as that of the whole specific heat of the oxy- 
gen gas in the other case. But it will not be contended, that the 
whole specific heat of the oxygen gas amounted to no more than 480 
degrees : for analogy would lead us to conclude, that the latent heat 
due to its gaseous state (including that of the previous state of liqui- 
dity) must greatly exceed this quantity, and if we add all the caloric of 
temperature, in a substance of a large capacity for heat, from the na~ 
tural zero up to the temperature of the experiment, we shall proba- 
bly underrate the quantity at three or four times 480°. The question 
then is, whence does it happen that 480° of uncombined heat could aid 
the expansion of the nitrogen gas, as much as four times this quantity 
entering with the oxygen? A reason, it appears to me, can only be 
found in the following explanation. The latter heat is so far opposed 
by a mutual attraction between the atoms of the oxygen, that its free 
effective elastic power equals only that of the 480° in the other case. 
Tf then any inference can be drawn from the equable expansion of a 
gas from equal increments of heat, it is certainly this ; that a power- 
ful attraction subsists between the gaseous atoms, reducing the elastici- 
ty of their large quantity of specific heat, in so great a degree, as to 
leave an effective elasticity equal only to what would be due to one- 
third or one-fourth as much heat. But the attraction cannot be appa- 
rent, because it is veiled beneath the excess of the elastic power. | 
The alleged fact that all gases have the same ratio of expansion has 
also been proposed as an argument against the existence of attraction 
between particles in a gaseous state. It is said that all gases have the 
same ratio of expansion, because the force opposing expansion is the 
same in all, namely, the pressure of the air ; and that if an attraction be 
admitted between the particles of a gas it must be considered as equal 
in every gas, for otherwise the ratio of expansion would not be the 
- game in all, and hence that there exists no attraction, for it cannot be 
considered as equal in all gases. Mature reflection will perhaps in- 
duce a different view of the subject. Though a certain change of tem- 
perature may produce an equal change in the mass of all gases, yet the 
separation of the particles may be scarcely the same in any two, for we 
