﻿Dr. Guyot on the Forms and Forces of Matter. 411 



fore, from the change of place effected under our eyes by 

 bodies themselves. Hence motion has been defined as the 

 motion of a body from one point of space to another. In order 

 that this definition might be exact, it would be necessary to say, 

 {( motion is the passage of bodies and atoms from one point of 

 space to another," because a particle, a molecule which we 

 can neither see nor touch, may also change place in the body of 

 which it forms part, and such is clearly a motion identical in 

 principle with the motion of bodies. The difference of the two 

 motions is only relative ; the one is exterior to, the other is in- 

 terior, in the body. But, wonderful to relate, observation of all 

 the phenomena of nature shows that they transform themselves 

 the one into the other, and are thus mutually connected and 

 complementary. The more of exterior motion a body accom- 

 plishes, the less is there of internal motion, and inversely. In 

 other words, the same quantity of matter always possesses the 

 same amount of motion. 



The inertia of matter is therefore an error. " What does it 

 signify?" say the learned who are more mechanicians than phi- 

 losophers ; " if the hypothesis of inertia permits us to calculate 

 all the facts of equilibrium of motion and of force which 

 occur on the surface of the earth, or rather in our physical and 

 mechanical operations, that is all we want. Whether an hy- 

 pothesis be true or false, if it be in accord with facts, if it be a 

 sure guide for practical questions, we call it true." 



I grant that a mechanic or practical man may hold such lan- 

 guage ; but they who feel the importance of truth, they who 

 understand that its quest is the most beautiful mission of the 

 human mind, and that its discovery and enunciation infallibly 

 guide humanity in the path of moral and material progress, 

 such, I say, will never admit that a false hypothesis can have 

 the same value as a true one, they will never allow that the at- 

 mospheric vacuum is as well explained by the horror of nature 

 as by the weight of the atmospheric column ; and yet these two 

 explanations express equally well the same fact. Inertia is an 

 hypothesis as little refined as that of the horror of a vacuum ; 

 it explains nothing, and stereotypes error in face of the most 

 brilliant truths. Does inertia explain the motion of the heavenly 

 bodies ? Does it explain the motions of animals ? No. But 

 the sidereal systems comprehend all known matter; and animal 

 organizations form the last term of material combinations. 

 Inertia therefore remains impotent in regard to the spontaneous 

 phenomena of the one or the other kind; between the alpha and 

 omega of the world it only claims a puny territory, namely the 

 relative movement and rest of bodies in equilibrium amongst 

 themselves in a system full of life. ./ 



