This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 Excerpt: ...farthest from the earth, happens eight minutes later than is computed by the mean motion so determined. When Jupiter is in opposition, it happens eight minutes sooner than according to the mean motion so determined. From a great variety of observations, it consequently appears that the velocity of light is such that, moving uniformly, it takes sixteen minutes to move over the diameter of the earth's orbit, or eight minutes in moving from the sun to us. This velocity is about 10,000 times greater than the velocity of the earth, which moves nineteen miles in a second. 206. On The Aberration Of The Fixed Stabs And Planets.--Another proof of the velocity of light is derived from the aberration of the fixed stars. The fixed stars' appear, by observations made with accurate instruments, to have a email annual motion, returning at the end of a year precisely to the same place. A star near the pole of the ecliptic appears to describe about that pole a small circle parallel to the ecliptic; the diameter of this circle is 40"'9. Stars in the ecliptic appear to describe small arcs of the ecliptic 40"9 in length. And all stars between the ecliptic and its poles appear annually to describe ellipses, the greater axes of which are parallel to the ecliptic, and equal to 40"'9. The axis minor is found by diminishing 40' 9 in the proportion of the sine of the star's latitude to radius. These phenomena cannot take place from the parallax of the annual orbit, because by it the latitude of a star would be greatest when in opposition to the sun, whereas then there is no aberration in latitude. 207. Dr. Bradley, who first discovered this apparent annual motion, when endeavouring to discover the parallax of 7 Draconis, also first explained the cause of it. It arises...
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