W. A. Norton—Molecular and Cosmical Physics. 447 
place. Now we have seen that contiguous molecular envelopes 
attract each other; and that the molecules at the surface of 
bodies, and of gases are, in all probability, in that ‘ primary 
condition” in which any expansion of an envelope enhances 
its attractive action. The tendency of the mutual actions of 
the two molecules supposed, is, therefore, to augment the range 
of the effective attraction of each (that is, to increase the dis- 
iminish the exterior repulsion. It is 
it is ap ntly on y ina few exceptional cases that the interior 
molecules of a liquid or solid are in the primary condition in 
which heat tends indirectly to induce an attraction. — In fact the 
same amount of heat which has been developed in the union 
of two molecules ought to suffice to dissociate them. 
