I venture to premise the successful solution of the problem will be accompanied with the greatest advance to science that has been known for a long time. The problem to be solved may be stated thus: "Does the Aether surrounding a planet or sun or any body in space move with that body, or does it allow the body to pass through it?" Up to the present, opinions on the subject have been varied and conflicting. Some scientists hold that the planetary and other bodies in space pass through the Aether without disturbing it, while others hold that part of the Aether is carried along by the moving planet. Fresnel assumed that the surrounding Aether was carried along by the earth, so that all relative phenomena would be the same as if the earth were at rest. Fizeau, from experiments which he conducted on running water, also came to the same conclusion. With the old idea of a frictionless medium, some of the present accepted theories are altogether untenable, because, if Aether is frictionless, how can it be carried along with the moving body, unless it is held bound to that body? and how can it be held bound to that body if it is frictionless? The whole view of the Aether is, however, changed by the conception of the Aether put forward in Chapter IV. Aether is Matter, and being matter it is also gravitative, and therefore is just as much subject to the Law of Gravitation as any other kind of matter, as Young stated in his Fourth Hypothesis (Art. 45). We will therefore attack the problem of the relative motion of the earth and the Aether around it from this new standpoint. In order to be strictly philosophical, we must base our hypothesis and conception on experience and observation. Where in the whole of planetary phenomena do we find similar conditions which exist between the Aether and the earth? Such conditions are alone to be found between the atmosphere and the earth. The analogy between the atmosphere and the earth, and the Aether and the earth is very striking, as the following comparisons will prove. The atmosphere (when pure) is invisible, so is the Aether. The atmosphere is atomic, the Aether is also atomic. Both are subject to the same laws of elasticity and density, and both are gravitative, according to our conception of the Aether. Now what is the effect of any large revolving body on a liquid or gaseous medium surrounding that revolving body?