1833.] Attraction and Repulsion. 455 
the same great author has shewn. For the attraction of a body in the 
mass (i.e. gravitation) depends wholly on this supposition. This 
same property we have seen* must belong to the other attraction of 
atoms. Secondly. The absolute force of gravitation varies as the 
mass. This, we have also seent, must be a property of the attraction 
of atoms chemically considered.—Thirdly. By decreasing the mass, in 
gravitation, until the force operating only between a few or single 
atoms, this force would become imperceptible at a very small distance, 
which exactly agrees with the attraction of atoms in question?. 
Fourthly. It has been above§, [ think, clearly shewn that the attrac- 
tion of atoms, as conneeted with chemistry, is universal ; and is there- 
fore in this respect perfectly similar to the attraction of atoms named 
gravitation. 
We have here two forces exerted by the very same atoms, (namely 
those of which all masses in nature are composed,) and possessing the 
same properties, as far as a comparison can be carried on between 
them ; and this extending through numerous particulars ; whence we may 
conclude, that both are the same force differing only in the accident of 
distance, from whence it has acquired distinct names—and therefore, 
since, by the above-mentioned discovery of Newron, the forces of 
atoms composing gravitation vary inversely as the square of their dis- 
tances, this force must still obey the same law, when considered 
under the name of contiguous attraction. 
The truth of this doctrine, which I have been endeavouring to de- 
monstrate generally, will I think be placed beyond all question, by 
the consideration of the following case. 
A celebrated author, whom I have already quoted, has adduced the 
spherical figure of a drop of water in proof of cohesion operating 
throughout all its particles. Let us now suppose such a drop, situated 
in absolute space, to be enlarged by an accession of matter, until it be- 
came an ocean. This ocean would unquestionably retain the figure 
of a sphere ; its parts being kept together by the same force, not at all 
changed in quality, but only increased in quantity. From having been 
once a drop, it would become a planet, and its attraction, which was 
called cohesion, would now be considered as gravitation. 
In addition to this, it may be remarked, that part of the fluid, pass- 
ing into vapor, would form an atmosphere around the planet, (admit- 
ting that it was exposed to the usual source of heat.) The force, 
which detained this atmosphere on the surface of the planet, would 
constitute its gravitation, which would be no other than the cohesive 
* Vide page 443. + Vide page 451, Head 3. + Vide page 443, § Vide page 450. 
