10 “NATURE AND LIFE. 
If the smallest parts which we can imagine and distin- 
guish in bodies differ from each other only by the nature of 
the motions to which they are subjected, if motion alone 
rules and determines the variety of different attributes 
which characterize these atoms, if, in a word, the unity of 
matter exists—and it must exist—what is this fundamental 
and primary matter whence all the rest proceed? How 
shall we represent it to our minds? Every thing leads to 
the belief that it is not essentially distinguished from the 
ether, and consists in atoms of ether more or less strongly 
held together. It is objected that the ether is imponder- 
able; but that is an unfounded objection. Doubtless it 
cannot be weighed; to do that we must compare a space 
filled with ether to a space empty of ether; and we are 
evidently unable to isolate this subtile agent, whose par- 
ticles counterpoise each other with perfect equilibrium 
throughout the universe. Yet many facts attest its pro- 
digious elasticity. A flash of lightning is nothing more 
than a disturbance of equilibrium in the ether, yet no one 
will deny that lightning performs an immense work. How- 
ever this may be, it is impossible to think of the energies 
that make up the atom otherwise than as of pure force, 
and the ether itself, whose existence is demonstrated by 
the whole of physics, can be no otherwise defined than by 
the attributes of force.* It follows from this that atoms, 
the last conclusion of chemistry, and ether, the last con- 
clusion of physics, are substantially alike, although they 
form two distinct degrees, two unequal values, of the 
same original activity. All those physico-chemical ener- 
gies, as well as the analogous energies of life, only show 
themselves to us, save in rare exceptions, clothed with that 
1 “Setting aside any theory, it would be hard to find in all these terms, 
dilatation, propagation, radiation, vibration, reflectien, refraction, attrac- 
tion, repulsion, polarization, etc., any thing else than phenomena of mo- 
tion.” —CHARLES DE REmusat, “ Philosophical Essays,” vol. ii., On Matter, 
