The theory of the transmission of vibrations of Radiant Energy by means of "waves" in the Ether, or "something that takes the place of the Ether," has been mentioned in other parts of the book. Referring again to it, the writer would say that he thinks it probable that the "waves" coming in contact with the countless Corpuscles in the Earth's atmosphere, communicate a high rate of motion to them, the result being that they take on the vibrations immediately, and pass along with the "wave" current--the result being that much that we consider as waves of Light, Heat and Electricity are but streams of these Corpuscles in which vibrations have been awakened by the "waves." This idea will help to explain some of the phenomena of Light, which seemed more understandable under the old Light-Corpuscle theory of Newton than under the "wave" theory of recent years. The idea is advanced merely for the purpose of setting down the thought, for it plays no important part in the theory of the book. Another matter that should not be overlooked in connection with Light and Heat and Electricity is that Particles absorb or "catch" the vibrations in different degrees, their receptivity depending upon their particular vibratory mode, or "custom of their kind." If unable to "absorb" the vibrations, they "reflect" them. Substance, of any particular kind, absorb Heat in the degree of its atomic weight. In the next chapter we shall learn something of The Law of Attraction, that wonderful Law that makes possible any Motion or Radiant Energy. CHAPTER X THE LAW OF ATTRACTION In the previous chapters we have seen that all forms of Radiant Energy, _viz._, Light, Heat, Electricity and Magnetism, arose from the Motion of the Particles of Substance. It now becomes important to learn just what cause this "Motions of the Particles." Science is somewhat hazy and foggy on this subject, but in a general way decides that it is caused by "the mutual relations and positions of the particles, arising from their respective attractive qualities," as a recent writer has expressed it. Well, this is better than the old way of seeking refuge and retreat in a mere volume of dense words. It is indeed the only logical conclusion, this one that the operations of the Law of Attraction are manifested in the Motion of the Particles. This great Law of Attraction is the greatest Law in Nature. It operates on all planes of life. It is always in evidence. Let us consider it. Let us begin by considering the most magnificent and constant exhibition of that Law--Gravitation. Gravitation is the Riddle of the Universe, and the one form of Energy that balks Science--so much a mystery that Science does not even hazard a "guess" at its nature--no theory of the origin and nature of Gravitation is to be found in "the books." Let us see what Gravitation is.