1833.] Attraction and Repulsion. 513 
This passage exactly proposes the above law, that as particles ap- 
proach their affinity increases in a greater ratio than the repulsive 
force, or that the repulsive force varies in a less ratio than the attrac- 
tion. The inadequacy of this explanation may at once be shewn. 
If, between the atoms of steam, the attraction has become greater 
than the repulsion, and if the attraction varies in a greater ratio, 
i. e. increases faster as the atoms approach than the repulsion, the 
particles must come into actual contact. The equilibrium spoken of 
in this quotation, can no more take place than between the forces of 
the atoms, A and B, in the diagram, should they be once within the 
point of unstable equilibrium. 
It cannot then be a law of the repulsion of heat that it varies ina 
less inverse ratio than the attraction. 
Secondly.— Whether the compound repulsion from heat varies in 
the same inverse ratio of the distance as the attraction of the atoms 
of the body. 
Supposing it a law of repulsion that it varies in the same inverse 
ratio of the distance as the attraction, it is evident that if the two 
forces are equal at one distance, they will also be equal at any other ; 
and if one force be the greater at one distance, it will also be the grea- 
ter at any other ; and therefore likewise, if one force be less than the 
other at one distance, the same force will be less at any other. 
Let us apply this law to the explanation— 
First. —Of the constitution of solids. 
When any body passes from the liquid to the solid state, it is right- 
ly supposed, that by the abstraction of heat, the attraction is enabled 
to bring the atoms of the fluid within the distance at which from the 
form and qualities of those atoms, solidity naturally subsists. But 
according to this law ; as the attraction was more powerful at the 
greater, it will also be at the smaller, distance ; and, in the solid, all 
the heat would either be expelled or so compressed, that the atoms 
would be in absolute contact, which certainly is not the case ; for all 
solids are capable of contraction. 
Secondly.—Of the constitution of liquids. Although most philoso- 
phers admit the existence of an attraction between the atoms of liquids, 
yet many* consider the liquid state as depending solely on the pres- 
sure of the air; without which, all bodies would either be solids or 
gases. 
* BerTHouueT in his Chem, Statics. Translation by LAMBERT, page 352— 
And many others. 
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