274 Mr, Exley*s Application of 



among the rest, by the action of c ; hence, electric atoms, 

 if present, will form the lowest stratum. 



When there are several tenacious atoms in the vessel, 

 each will similarly retain an atmospherule on its surface. 



Next, let there be two tenacious atoms, a and Z>, in the 

 vessel, and let their forces on an ethereal atom at g be each 

 resolved into two, one in R N, passing through their 

 centres, the other in g d, perpendicular to R N. When d 

 is between a and b, the forces in R N oppose each other, 

 and act by their difference ; but in other cases by their 

 sum : again, the forces in g d always act according to their 

 sum ; and, as these forces are supported by equal forces on 

 the opposite side, the constant effect is to condense ethereal 

 matter on the line R N, where the most powerful ethereal 

 atoms, and especially the electric atoms will be chiefly 

 collected, for the reasons assigned above. 



Hence, there will be an atom, as z, in a b, undisturbed 

 in the middle, when a b are equal, in other cases, nearer to 

 the less powerful atoms : and the atoms condensed in the 

 line a b will be equally pressed and supported on all sides 

 by the contiguous atoms. 



Cor, When electric atoms are in the vessel, they also 

 will retain small atmospherules of ethereal matter, which, 

 although less dense than those of the tenacious atoms, will 

 have considerable density if the spheres of repulsion of the 

 electric atoms be very small, which is probable. It is also 

 manifest, that the atmospherules of both the tenacious and 

 electric atoms will be more dense, when the ethereal atoms 

 are more compressed or crowded together. 



Prop. 2. Things being as in prop. 1, the actions of any 

 two atoms on each other, combined with the mutual actions 

 of the whole mass on each of the two, will be a repelling 

 force between them, inversely proportional to their distance. 



Let s be the centre of the vessel in which ethereal atoms 

 of one sort are compressed by a considerable force: then, 

 since the absolute force of the ethereal atoms is very small, 

 the distance between their centres will also be exceedingly 

 small, constituting points in a sphere, such as in Newton's 

 73rd Prop. B. 1. Prin., and by that proposition any cor- 

 puscle or atom a, placed at any point of this sphere, will, by 

 the mutual actions of the whole mass be attracted by a 



