ASTRONOMY
What proofs are there that the earth is round? 573.
How old is the earth estimated to be? 573.
What are the four principal motions of the earth? 573*
When is the summer solstice? 574.
When is the winter solstice? 574.
On what days occur the vernal and autumnal equinoxes? 574.
What are the five zones? 574.
At what highest points north and south do the sun's ^rays fall vertically? 574.
ASTEROIDS.
How do the heat of the sun and the circulation of water affect the earth's surface? 574.
What are the asteroids? 126.
How has photography helped to discover them? 126.
Why was the discovery of Eros important? 126.
COMETS.
What bodies visit the solar system from other parts of the universe? 128, 432.
Of what three parts are comets composed? 432.
What comets may be seen but once, and what comets have been observed repeatedly? 433.
Where do we find a spectrum identical with that of a comet? 433.
What mystery is there in connection with the tail of a comet? 433.
What comet will return in 1911? 433,
THE MOON.
What is the name of the earth's satellite? 1259. What is the distance of the moon from the earth? 1259. Why could a man standing on the moon throw a stone six times as
far as he could if on the earth? 1259. How do we know that the moon has neither atmosphere nor water?
1259.
What various phases does the moon present? 1259. What are Kepler's three laws of planetary motion? 1900.
ECLIPSES.
What is a solar eclipse? 579. What is a lunar eclipse? 579.
What is the difference between a total and an annular eclipse? 579. What conditions are necessary for a solar eclipse? 579.
METEORS.
When are shooting stars called meteoric stones? 129. Why is it that the earth is unharmed by the seven and a half million
meteors met with daily? 1212. Of what materials are aerolites composed? 1212. What are fireballs? 1212. What are radiants? 1212.
When was the most wonderful display of meteors ever seen? 1212. What is the cause of a meteoric shower? 1212. What is the connection between comets and meteors? 1212.
STARS. What has the spectroscope revealed concerning the "fixed stars"?
1813.
What determines the grouping of the stars? 1813. How many groups are there? 1813.
How many stars are there of the first magnitude? 1813. What important stars belong to the second group? 1813. How many stars may be seen without the aid of a glass? 1813. What is the name of the earth's nearest neighbor? 1813, 128. Do the fixed stars move? 1813. What is the zodiac? 2132. How many signs are there in the zodiacf 2132.
2308
