and her density is 5.66 times that
of water. She is attended by a single satellite, the moon, which
revolves round her in 27.3 days, at a distance of 238,000 miles. The
moon rotates on her axis in about the same time, and hence we can only
see one side of her. She is 2,160 miles in diameter, but her mass is
only one-eightieth that of the earth. A pound weight on the moon would
scale six pounds on the earth. Having little or no atmosphere or water,
she is apparently a dead world.

"The red planet beyond the earth is Mars, who appears in the sky as a
ruddy gold or coppery star. He is 141 million miles from the sun,
travels his orbit in 687 days, and wheels round his axis in 24 hours 37
minutes. His diameter is 4,200 miles, and his mass about one-ninth that
of the earth. A body weighing two pounds on the earth would only make
half a pound on Mars. As you know, his atmosphere is clear and thin, his
surface flat, and subject to floods from the melting of the polar snows.
Mars is evidently a colder and more aged planet than the earth.

"He is accompanied by two little moons, Phobos (Fear), which is from ten
to forty miles in diameter, and revolves round him in 7 hours 39
minutes, at a distance of 6,000 miles, a fact unparalleled in astronomy;
and Deimos (Rout), who completes a revolution in 30 hours 18 minutes, at
a distance of 14,500 miles.

"About 400 planetoids have been discovered up to now, but we are always
catching more of them. Medusa, the nearest, is 198 million miles, and
Thule, the farthest, is 396 million miles from the sun. Vesta, the
brightest and probably the largest, a pale yellow, or, as some say,
bluish white orb, visible with the naked eye, is from 200 to 400 miles
in diameter. It is impossible to say which is the smallest. Probably the
mass of the whole is not greater than one quarter that of the earth.

"Jupiter, surnamed the 'giant planet,' who almost rivals Venus in her
splendour, is 480 million miles from the sun; travels round his orbit in
12 years less 50 days; and is believed to whirl round his axis in 10
hours. His diameter is 85,000 miles, and his bulk is not only 1,200
times that of the earth, but exceeds that of all the other planets put
together. Nevertheless, his mass is only 200 to 300 times that of the
earth, for his density is not much greater than that of water. What we
see is evidently his vaporous atmosphere, which is marked by coloured
spots and bands or belts, probably caused by st