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Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1846 Excerpt: ... of an orange, ns m fig. 1; it is then called an oblate spheroid, because it is flattened at the poles N and S. Such Fig. 2. Is the form of the earth and planets. When, on the contrary, it is drawn out of the poles like an egg, as in Jig. 2, it is called a prolate spheroid. It is evident that in both these solida the radii C 9, C a, CN, &.c.,are generally unequal; whereas in the sphere they are all equal. Note 10, p. 4.--Center of gravity. A point in every body, which if supported, the body will remain at rest in what-2 ever position it may be placed. About that point all the parts exactly balance one another. The cecsual bodies attract each other as if each were condensed into a single particle situate in the center of gravity, or the particle situate in Ihe center of gravity of each may be regarded as possessing the resultant power of the innumerable oblique forces which constitute the whole attraction of the body. Note 11, pp. 4,6.--Poles and equator. Let fig. 1 or 3 represent the earth, C its center, NCS the axis of rotation, or the imaginary line about which it performs its daily revolution. Then N and S are the north and south poles, and the great circle q E Q, which divides the earth into two equal parts, is the equator. The earth is flattened at the poles fig. 1, the equatorial diameter, q Q, exceeding the polar dUnneter, N S, by about 26 PS miles. Lesser circles, A U G, which are parallel to the equator, are circles or parallels of latitude, which is estimated in degrees, minutes, and seconds, north and south of the equator, every place in the same parallel having the same latitude: Greenwichisin the parallel of 5128''40. Thus terrestrial latitude is the angular distance between the direction of a plumb-line at any plsce and the plane of the equ...
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