Page:Various Forces of Matter.djvu/118



whether we shall be too deep to-day or not. Remember, that we spoke of the attraction by gravitation of all bodies to all bodies by their simple approach. Remember, that we spoke of the attraction of particles of the same kind to each other,—that power which keeps them together in masses,—iron attracted to iron, brass to brass, or water to water. Remember, that we found, on looking into water, that there were particles of two different kinds attracted to each other; and this was a great step beyond the first simple attraction of gravitation; because here we deal with attraction between different kinds of matter. The hydrogen could attract the oxygen and reduce it to water, but it could not attract any of its own particles, so that there we obtained a first indication of the existence of two attractions.