Although the Ether, as we have seen, is a purely theoretical substance, yet Science has found it reasonable to conclude that it must be possessed of certain attributes in order to account for certain known facts. Thus, it is said to be frictionless, else the worlds, suns and planets could not pass freely through it, nor could the light and heat waves travel at such a tremendous rate. It also is thought to have something like Inertia, because Motion once started in it persists until stopped; because it is at a state of rest until Motion is imparted to it; and because it takes a fraction of time to impart motion to it. It is thought to be different from Substance in any of its known forms, for many reasons, among such being the fact that no known form of Substance could carry vibrations through space at the rate of 184,000 miles a second. And Light and Heat waves travel at that rate, and have forms and shapes, and lengths of their own. Light for instance, vibrates on two planes, and a light-wave is something like a Greek cross, thus (-|-), having a horizontal and a vertical line, or plane of vibration. And the Ether cannot be a fluid of any degree, because a fluid cannot transmit cross vibrations at all. And it cannot be a Solid, because a Solid could not stand vibrations at such a terrific speed, and still remain a Solid. And yet, to transmit the two-plane light waves, the Ether must have a certain degree of Rigidity, else the waves could not travel. Lord Kelvin estimated this degree of Rigidity as about 19,000,000,000th of the rigidity of the hardest steel. So, you see, Science is compelled to assume that the Ether is "a continuous, Frictionless medium, possessing both Inertia and Rigidity." Some scientists have thought it to be a kind of "elastic jelly." Of the Ether, Prof. Oliver Lodge has said, "We have to try and realize the idea of a perfectly continuous, subtle, incompressible substance, pervading all Space, and penetrating between the molecules of ordinary Matter, which are imbedded in it, and connected to one another by its means. And we must regard it as the one universal medium by which all actions between bodies are carried on. This, then, is its function--to act as the transmitter of motion and energy." To give you an idea of the wonderful thing that Science is compelled to think of the Ether as being, by reason of the qualities it is compelled to ascribe to it--although it confesses itself unable to "imagine" the nature of the "Thing" which it has created in bits by the adding and bestowing of qualities which were made necessary by the logical requirements of the case--let us take a hurried view of the Thing as the several departments of Science say it must be thought of.