In the first place, Gravitation, so far as is known, is not dependent upon, caused by, or maintained by, any other Force or form of Energy. Nor does it seem to be derived from some great reservoir, from which it obtains its supply of Energy. On the contrary, it seems to be a "thing-in-itself," self-supporting, self-existing--an intrinsic thing, in fact. It does not seem to be lost to bodies by radiation. And consequently there seems to be no need of a body replenishing its supply, as there is no loss. Gravitation seems to be a constant _something_, remaining always with bodies and neither being lost or acquired. It exists between the Atoms, Molecules, Masses--all in the same way. In fact, one is tempted to think of the planets and worlds in space, as Molecules of some greater Mass held together by Gravitation just as are the Molecules held together. Remember, that the Molecules and Atoms are not in absolute contact, _but there is always a "space" between them_, although the space or distance may be "insensible" to us. "As above, so below," says the old occult aphorism, and it seems to be so. Then again, Gravitation is believed to act _instantaneously_, and does not require Time to pass between bodies, as does Light, Heat, Electricity, Magnetism--Radiant Energy. Light travels through the Ether (as light-waves) at the rate of 184,000 miles a second. The same is true of Heat and of Electricity. But Gravitation travels instantaneously. For instance, if a new star were to spring into existence at some inconceivable distance from the earth it would require thousands of years for its light to reach us. But its Attraction of Gravitation would be felt _instantly_. Do you realize what this means? It means that Gravitation is in some way connected with the Ether, or "conveying medium," that an impulse communicated at some point of space trillions of miles away is felt _at once_ at our point in space, and vice versa. There is some awful mystery here, and the laws of Substance, and Force, as generally understood, do not account for it. And the theories regarding the Ether do not throw light upon it. _But wait a bit!_ But more than this. Science holds that Gravitation _does not require a medium_--that it seems to be its own medium--needing no "Ether" or other medium to transmit its influence. In this respect also, Gravitation differs from the form of Radiant Energy. And more, it is not "cut-off" or interfered with by any intervening body, for its force operates through such intervening bodies. For instance, in an eclipse of the Sun, the Moon passes between the Earth and the Sun, but the Gravitation is not affected in the slightest, for the bodies would evidence such change immediately were it to occur. So Gravitation acts instantaneously; is its own medium, and may not be interfered with by an intervening body. It, indeed, is in a different "class" from Light, Heat and Electricity. And now let us consider the other forms of Attraction.