The Sun's Three Motions

The sim has three known motions: 1. An axial rotation, which is plainly shown by the appearance and disappearanco of well-known spots upon his surface. The mean period of thia axial motion is 23 1-3 of our days. 2. A motion around the center of gravity of the whole solar S57stem - a motion which can only be ascertained by the use of very delicate instrumenta on account of his great mass, which ia greater than the total of all the other bodies of the system combined. 3. A progressive motion through space in the direction of the constellation of Hercules. The rate of speed of this last namod motion is not known, but it is estimated to bo 150,000,000 miles per year, and some investigators even think it possible that the rate will exceed the abovc esüraate by at least biL_