454 On the two great powers, [Sppr. 
of expansion in liquids, and the equable expansion of gases from de- 
creasing additions of heat. The former can only be accounted for, by 
supposing that its chief opponent force, the attraction, decreases. The 
latter also requires the admission of an attraction between all gaseous 
particles, and that this force decreases likewise. For, did it not decrease, 
gases (as it was there demonstrated) could not expand as much from 
certain additions of caloric of temperature, as from their specific heat, 
so much more in quantity. 
In Dr. Rexs’s Cyclopedia* we find another author, who expresses a 
very different opinion. ‘‘ There is,” he says, ‘‘ an attraction, which is 
found to obtain in the minute particles, whereof all bodies are com- 
posed, which attract each other, at or near the point of contact, with 
a force much superior to that of gravity, but which, at any distance 
from it, decreases much faster, than the power of gravity.” 
And others, observing the apparently great decrease in the force of 
attraction, as particles are separated from each other, have supposed 
that it must vary as the inverse cube, or some higher power of the 
distance. 
All these views have doubtless arisen, from attending to the appa- 
rent, rather than the actual, force of attraction. Since attraction, 
whenever presented to observation, is always opposed by a divellent 
force, the law of the simple force cannot be investigated by any direct 
experiment from its immediate effects. 
There is however the strongest reason for concluding that contigu- 
ous attraction, as treated of in chemistry, is identical with the great uni- 
versal power, gravitation. 
This opinion has been hinted at by philosophers from an early age 
of this science, and among them by Sir Humpurey Davyt. But it 
may be demonstrated, as I think, in the most satisfactory manner, from 
the following considerations. 
lst. The great Newron has demonstrated, that the gravitation, 
which prevails throughout the bodies of the system, is composed of 
the sums of the attractions between the atoms of the several bodies. 
And thus it is, strictly speaking, an attraction of atoms; and it is ex- 
erted between the same atoms as the attraction, which usually bears 
that name. 
2ndly. It will be found to possess the same properties also.—First. 
That attraction of atoms, which constitutes gravitation, increases or 
decreases as the distance at which it operates is less or greater. This 
* Art. Attraction. + Sir H. Davy’s Elements of Chem. Philosophy, p. 68. 
