REPULSION. 
That the particles of fluids are not destitute of an 
attraction for each other, is evident from numberless 
facts. The particles of water draw one another after 
them in cases of capillary attraction; which is proba 
bly owing to the attraction of cohesion. It is owing 
to the attraction of cohesion, too, that small quantities 
of water form themselves into spheres; nor is this at 
traction so weak as not to be perceptible. If a small 
plate of glass be laid upon a globule of mercury, the 
globule, notwithstanding the pressure, continues to pre 
serve its round figure. If the plate be gradually char 
ged with weights one after another, the mercury be 
comes thinner and thinner, and extends itself in the 
form of à plate ; but as soon as the weights are re 
moved, it recovers its globular figure again, and pushes 
up the glass before it. Here we see the attraction of 
cohesion, not only superior to gravitation, but actually 
overcoming an external force *. And if the work 
man, after charging his plate of glass with weights, 
when he is forming mirrors, happen to remove these 
weights, the mereury which had been forced from under 
the glass, and was going to separate, is drawn back to 
its place, and the glass again pushed up. Nor is the 
attraction of cohesion confined to solids and liquids; it 
cannot be doubted, that it exists also in gases ; at least 
it is evident, that there subsists an attraction between 
gases of a different kind: for although oxygen and azo 
tic gas are of different gravities, and ought therefore to 
occupy different parts of the atmosphere, we find them 
always mixed together; and this can only be ascribed to 
an attraction. 
Morveau, Encycl. Metb. Affnité, p. 543. 
245 
n N.