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ROTATION OF EARTH Gradually, all the problems which arose out of the belief that the earth was in motion were resolved. The hypothesis like rotation and revolution of the earth, the inclination of its axis at 233, the existence of an atmosphere enveloping the whole earth and the theory of gravitation, etc, fully supported the theory of the earth's motion. Some questions of ancient origin, such as how birds iying in the sky can reach their nests; why all things, on the earth are not destroyed by the tremendous speed of strong winds, why flags etc. do not point to the same direction, were resolved by the presumption of existence of almosphere. Things uke the birds, the arrows, the aeroplanes, which take off from the earth, have a motion of their own, and at the same time being in the atmosphere possess another motion equal to that of the earth, eg when a bee is flying in a compartment of a train, it has its own motion of flymg here and there in the atmosphere of the compartment ; but at the same time it has another motion also which is equal to the speed of the train Ir the same way the arrow thrown out in the space returns to the earth, and the flowing matters like the sea and the river etc., continue to remain on the earth All these are due to the gravitation of the earth and the earth remains unsupported in the space due to the gravitation of other planets. Again, another question arose that, if the earth moves uniformly round the sun, how there comes a change in the seasons ? This question is
