The Complete Works of Thomas Dick Volume 2

The Complete Works of Thomas Dick Volume 2

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1856 edition. Excerpt: the distance of the eye; and if this distance were exceedingly increased. the whole stratum might at last be drawn together into a lucid spot of any shape, according to the position, length and hight of the stratum. In order to determine those points, Sir W. llerschel put in practice a method which he calls gailging the heavens, which consists in repeatedly counting the number of stars in the fields of view very near each other, i y which he obtained I THE MILKY WAY. mean of the number of stars in that part of the heavens. He then proceeds on the supposition deduces the length of his visual ray, or the distance through which his telesc had penetrated, or, in other wor, the distance of the remotest stars in that particular region of the heavens. To illustrate this, let us sup-' pose the Milky Way It nebula, and that the sun is not placed in its center. Then, on the supposition that the stars ' are nearly equally scattered, it is evident that the part of the Milky Way where the stars are the most numerous extend farthest from the sun, and the parts where they are less numerous must extend to a less dislunco Proceedin on these grounds, Sir W. Herschel Eound the length of his visual ' my for different parts of the heavens. ' In some cases he found it equal to 497 times the distance of Sirius, supposed to be the nearest star, as formerly its stated. The following is a representa-l' tion of a section of the nebula of the ' Milky Way, according to his delineation. This section is one which makes an angle of thirty-five degrees with, our equator, crossing it in 124% and 304 degrees. A celestial globe adjusted to the latitude of fifty-five degrees north, and having 0' Ceti near the meridian, will have the plane of this more

Product details

  • 12-17
  • Paperback | 712 pages
  • 189 x 246 x 36mm | 1,247g
  • United States
  • English
  • black & white illustrations
  • 1236829115
  • 9781236829115