ASTEROIDS, OR PLANETOIDS.

Of these none, except perhaps occasionally Ceres and Vesta, can be

seen by the unaided eye. This is on account of their small size, their

diameters ranging from fifty to two hundred and twenty-eight miles. The

theory respecting these bodies is that they are portions of a larger one

that in some manner became disintegrated, and each part obeying the laws

of gravitation, formed itself into a separate sphere.

The Chautauquan, Vol. 04, March 1884, No. 6 · 第 45 / 158 题