THE CONSTITUTION OF MATTER. 9 
This experiment is especially the true image of what 
Faraday was as a metaphysician. For him nothing had 
so great a charm as those serene transparent regions, in 
which science, cleared of impurities, appeared to his great 
mind in all the glory of its power and splendor. He 
yielded himself to it with absolute abandonment. He 
particularly loved to dwell upon the problem which is 
now engaging us: ‘‘ What do we know of an atom apart 
from force?” he exclaims. ‘‘ You conceive a nucleus 
which may be called a, and you surround it with forces 
which may be called m, to my mind your @ or nucleus 
vanishes, and substance consists in the energy of m. In 
fact, what notion can we form of a nucleus independent 
of its energy?” <As he holds, matter fills all space, and 
gravitation is nothing else than one of the essentially con- 
stitutive forces of matter, perhaps even the only one. An 
eminent chemist, Henry Saint-Claire Deville, lately de- 
clared that, when bodies deemed to be simple combine 
with one another, they vanish, they are individually anni- 
hilated. For instance, he maintains that in sulphate of 
copper there is neither sulphur, nor oxygen, nor copper. 
Sulphur, oxygen, and copper, are composed, each of them, 
by a distinct system of definite vibrations of one energy, 
one single substance. The compound, sulphate of copper, 
answers to a different system, in which the motions are 
confounded that would produce the respective individuali- 
ties of its elements, sulphur, oxygen, and copper. More- 
over, Berthelot long ago expressed himself in exactly the 
same manner. As long ago as 1864 that savant said that 
the atoms of simple bodies might be composed of one and 
the same matter, distinguished only by the nature of the 
motions set up in it. This decisive saying a great num- 
ber of savants and philosophers in France and abroad have 
repeated and are still repeating, with good reason, as the 
expression of a solid truth. 
