16 NATURE AND LIFE. 
up with the existence of systems of unequal vibrations, of 
diversified media, and varying molecular arrangements. 
A fortiori, the phenomena of life will be incompatible with 
this universal unity of substance, this unchanging identity 
of force. 
The objective existence of things, the coming into re- 
ality of phenomena, can only be conceived, therefore, as 
the work of a certain number of differentiations taking 
place in the deep of that universal energy of primal mat- 
ter, which is the last result of our analysis of the world. 
Motion, of itself alone, is enough to explain a first attri- 
bute of that energy, namely, resistance, and its conse- 
quence, impenetrability ; but this is only on the condition 
that this motion shall take place in various directions.’ 
Two forces urged in opposite directions, and coming to a 
meeting, manifestly resist each other. It is probably by 
collisions of this sort that those variable condensations of 
matter, and those heterogeneous groupings of which the 
world presents the spectacle, have been determined. A 
rotary movement, communicated to a mass without weight, 
can only engender concentric spheres, which gravitate 
toward each other in consequence of pressure by the inter- 
posing ether. The famous experiments of Plateau are de- 
cisive in this respect. That accomplished physicist intro- 
duces oil into a mixture of water and alcohol, having 
exactly equal density with the oil itself. He inserts a me- 
tallic strip into the midst of this mass of oil, which is free 
1“ Any relation of action implies at least twofoldness. We have then 
at once dissimilarity, and it would be more correct to say, action takes 
place only between dissimilars. Between like things, action requires at 
least a difference of place, yet even with that difference like things act 
but slightly on each other. The production of such a phenomenon re- 
quires opposition in forces between them. In chemistry, only dissimilars 
act on each other. All Nature witnesses that a certain degree of differ- 
ence between bodies is needed for their mutual action.”—CHaRLEs DE RE- 
MUSAT. 
