Physical Geography
Format: Paperback
ISBN13: 9780217028103
Paperback|9780217028103
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Overview
Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: 32 CHAPTER III. Ancient observation of the Heavens.?Description of the Celestial Sphere? its Divisions transferred to the Earth.?The Sphericity of the Earth recognized?Its Magnitude conjectured.?Eratosthenes, his measurement of a degree?his method revived by Fresnel in the 17th century.? Snell's attempted triangulation.?Geodetic Surveys, France, Great Britain, India, Russia, andc.?Newton's Work.?Effects of Rotation on the Earth's figure.?Irregularities of Gravitation at the Surface.?Increase of Gravity from the Equator to the Pole?and of the length of Degrees. ?Figure and size of the Earth determined.?The Pendulum as a means of measuring Gravitation.?The Attraction of Mountains.?Schehallien. ?The Himalaya.?The Torsion Balance.?The Specific Density of the Earth. To the watchful Greeks on hill-tops, and to the shepherds of Assyrian plains, the stars and revolving heavens must have been deeply interesting objects. The stars were soon grouped, for facility of reference, into imaginary figures or constellations. The central portion of the heavens about the paths of the sun and planets, whither observation was most frequently directed, was the first to be marked out in this way; and a Zodiac or figured zone of the heavens was known to almost every ancient nation. Attention was directed also to the polar region, where the stars perform their circuits above the horizon, and the bear, as Homer sings, alone never bathes in the streams of ocean. Nor did the little bear, anciently called the Dog, and the remarkable star named the Cynosure (kvvoi ovpa) or Dog's tail, known at the present day as the Pole-star, round which the whole heavens turn, escape notice. But the contemplative spirit admires the constancy of the heavens more than their fancied imagery. The pole is immovab...
| ISBN-13 | 9780217028103 |
|---|---|
| ISBN-10 | 0217028101 |
| Weight | 1.05 Pounds |
| Dimensions | 9.00 x 6.00 x 0.72 In |
| List Price | $23.74 |
| Format | Paperback |
|---|---|
| Pages | 322 pages |
| Publisher | |
| Published On | 2009-08-01 |
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