138 WORK AND PLAY.

“Our poor little Earth!”

“xen so; this pea is the Earth, on a circle of four
hundred and thirty feet. Then comes Mars, a rather
large pin’s head, on a circle of six hundred and fifty-
four feet. But what have we here? Four grains of
sand, in orbits of from a thousand to twelve- hundred
feet: these are Juno, Ceres, Vesta, and Pallas.”

“T don’t know any of them,” said Bob Burnham.

“Perhaps, then, you will be better pleased with this —
orange, of moderate size, moving in a track nearly half
a mile across: it is named Jupiter. Next comes a
small orange, on a circle of four-fifths of a mile: it is
Saturn.”

“I thought,” said Mack, “that Saturn was larger
than his son.”

“A very common error,” replied the doctor. “But
here we have Uranus, or Herschel, a full-sized cherry,
or small plum, upon the circumference of a circle more
than a mile and a half. Lastly, Neptune, a good-sized
plum, on a circle two miles and a half in diameter.”

“T thought, sir,” said Burnham, “that Neptune was
the god of the sea ;” and the good-natured boy scratched
his head in much perplexity.

This was a signal for an outbreak of pent-up fun.
All broke out together on Burnham; and even Carl
could not help saying, “And now you find him omy a
good-sized plum—eh ?” :

“No, no,” replied Burnham, with an air of injured