Page:The fairy tales of science.djvu/217

Rh of a circle above a mile and a half in diameter; Neptune a somewhat larger plum, on the circumference of a circle about two miles and a third in diameter.

Having thus briefly glanced at the planetary satellites of the sun, we will now proceed to view, with equal briefness, that great centre of the system itself, which feeds and vivifies them all with its glorious rays. The stupendous globe which we call the sun, is about 1,400,000 times as large as our earth, its diameter being 885,000 miles! However, its density being only 0·2543 as compared to that of the earth, it contains only 354,936 times the mass or quantity of ponderable matter that the latter consists of. It turns on its axis in $25 1⁄4$ days, as proved by telescopic observations of certain dark spots on its surface. The sun apparently moves round the earth, though it is in reality the latter body which moves round the sun, in a nearly circular orbit, described in a plane, sensibly fixed, called the ecliptic. The ancients called that portion of the heavens in which the sun’s apparent orbit is performed the zodiac, and divided the great circle formed by the intersection of the plane of this orbit with the sphere of the heavens into twelve equal portions or signs, named in order—Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces. The sun, however, has also a real motion: he moves with the entire solar system in the direction of the constellation of Hercules in the western sky. The sun’s rays are