Leaning against the chimney-piece, where a bright fire crackled, while his companion looked at him with her large eyes full of curiosity, he began to speak with a sort of unconscious solemnity, as though he were discussing something with his own mind in the solitude of the woods.
*****
"What we see is only apparent. Reality is quite different.
"The sun apparently turns about us, rising every morning, setting at night; the earth where we are seems to be motionless: but the contrary is the truth. We live on a whirling projectile, thrown into space with a speed seventy-five times as great as that which carries a cannon-ball.
"Our ears are pleased by a harmonious concert. Sound does not exist; it is merely an impression of the senses produced by vibrations of a certain size and rapidity on the air, which in themselves are silent. There would be no sound without the acoustic nerve and the brain. In reality there is nothing but motion.
"The rainbow spreads its radiant circle; the rose and corn-flower, dripping with rain, glitter in the sun; the green meadow, the golden furrow, diversify the plain with their bright colors. There are no colors; there is no light,—there is nothing but the ether waves, which cause a vibration of the optic nerve. Appearances are deceitful. The sun warms and fertilizes; fire burns. There is no heat, only sensation; heat, like light, is but one form of motion,—invisible but supreme, sovereign motion!
*****
"Take a strong iron beam, like one of those used so generally in building nowadays. It is set up in space, ten metres high, between two walls which support its ends. It is 'solid.' In the middle of it is placed a weight of one, two, or ten thousand kilograms; but it does not even show this enormous weight,—a level would hardly find a depression in it. And yet this beam is composed of particles which do not touch each other, which are in perpetual vibration, which separate under the influence of heat, and are drawn together by cold. Tell me, if you please, in what the solidity of this bar of iron consists. Its material atoms? Assuredly not, since they do not touch. That solidity lies in molecular attraction,—that is to say, in an immaterial force.
"Speaking absolutely, solidity does not exist. Take up a heavy iron cannon-ball: this ball is composed of invisible molecules which do not touch each other. The continuity which the surface seems to have, and the apparent solidity of the ball are, then, pure illusions. To the mind which would analyze it, its inner structure is an eddying swarm of little gnats, like those darting about in the air on a summer day. Then suppose we heat this apparently solid ball: it will melt; heat it more, it will evaporate,—but without changing its nature for all that; gas or liquid, it will still be iron.
"We are in a house. All these walls, these floors, these carpets, this furniture, the marble mantelpiece, are also composed of particles which do not touch each other; and all these particles which constitute these objects are in constant motion, circulating around each other.