What Matter or Force may be, we have not as yet the slightest idea. Matter is only known to us by the forces it exerts or resists. It is possible that there may be but one species of ultimate parts (molecules or atoms?) of matter; but in the present state of chemical science, it is more philosophical to reason as if the ultimate parts of the various elementary bodies are distinct. However this may be, a particle of hydrogen, oxygen, sodium, or gold, exerts certain definite forces upon other particles; which forces, we have every reason to believe, will remain for ever unchanged, unless the so-called element should at some future time be decomposed.