Author Description

Excerpt from On the Connection of the Physical Sciences IT has been proved by Newton, that a particle of mat ter (n. 6) placed without the surface of a hollow sphere (n. Is attracted by it in the same manner as if the mass of the hollow sphere, or the whole matter it con tains, were collected into one dense particle in its center. The same is therefore true of a solid sphere, which may be supposed to consist of an infinite number of concentric hollow spheres (n. This, however, is not the case with a spheroid (n. But the celestial bodies are so nearly spherical, and at such remote distances from one another, that they attract and are attracted as if each were condensed into a single particle situate in its center of gravity (n. 10) - a circumstance which greatly facili tates the investigation of their motions. Newton has shown that the force which retains the moon in her orbit, is the same with that which causes heavy substances to fall at the surface of the earth. If the eafth were a sphere, and at rest, a body would be equally attracted, that is, it would have the same wei ht at every point of its surface, because the surface 0 a sphere is everywhere equally distant from its center. But as our planet is attened at the poles (n. And bulges at the equator, the weight of the same body gradually decreases from the poles, where it is greatest, to the equator, where it is least. There is, however, a certain mean (n. 12) latitude (n. Or part of the earth intermediate between the pole and the equator, where the attraction of the earth on bodies at its surface is the same as if it were a sphere; and experience shows that bodies there fall through feet in a second. The mean distance (n. 14) of the moon from the earth is about sixty times the mean radius (n. 15) of the earth. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical wo