the middle with the planets moving around him. The one
nearest to the sun is Mercury."

"It must be hot there!" cried Philip.

"I dare say that if we were in Mercury we should be scorched to ashes;
but if creatures live on that planet, God has given them a different
nature from ours, so that they may enjoy what would be dreadful to us.

"The next planet to Mercury is Venus. Venus is sometimes seen shining so
bright after sunset; then she is called the evening star. Some of the
time, a little before sunrise, she may be seen in the east; she is then
called the morning star.

"Venus can never be an evening star and a morning star at the same time
of the year. If you are watching her this evening before or after
sundown, there is no use getting up early to-morrow to look for her
again. For several weeks Venus remains an evening star, then gradually
disappears. Two months later you may see her in the east--a bright
morning star.

"Our earth is the third planet, and Mars is the fourth from the sun. Now
let us make a drawing of what we have been talking about.

"First open the compasses one inch; describe a circle, and make a dot on
its circumference, naming it Mercury. Write on this circle eighty-eight
days; this shows the time it takes Mercury to travel around the sun.
Make another circle three and one-half inches in diameter and make a dot
on it. This represents Venus. It takes Venus two hundred twenty-five
days to journey around the sun.

"The next circle we have to draw is a very interesting one to us. The
compasses must be opened two and one-half inches. The path made
represents the journey we take in three hundred sixty-five days.

"One more circle must be drawn to complete our little plan. This circle
must be eight inches in diameter. You see Mars is much farther from the
sun than our earth is. It takes him six hundred eighty-seven days to
make the trip around the sun. The other planets are too far away to be
put in this plan."

"O, Frank, you have missed the biggest of all--the moon!" said Philip.

"O, no, no!" exclaimed Frank. "The moon is quite a little ball. It is
less than seven thousand miles around her, while our earth is
twenty-five thousand miles around."

"Is that a little ball, Frank?"

"Yes, compared with the sun and the planets. The moon is what is called
a satellite--that is, a servant or an attendant. She is a satellite of
our earth. She keeps circling round and round our earth, while we go