as,
instead of staying in the winter, would long since have moved back
through autumn into summer, and so on. In about 1400 years it would
travel through the entire circle of the seasons, as it would come some
six hours earlier every year than it did the last. In like manner the
Fourth of July would gradually fall back into spring, then into winter;
and the fire-works would have to be set off in the midst of a
snow-storm. The old Romans saw the difficulty; and, to prevent it,
Julius Caesar added an extra day to every fourth year, which you see is
the same thing as adding one-fourth of a day to each year, only it is
much more convenient. This was done because the earth requires nearly
365-1/4 days to move round the sun. The year that receives the extra day
is called, as you know, leap-year. But even this did not keep the
calendar exactly right. In the course of time other changes had to be
made, the greatest of which was in 1582, when Pope Gregory XIII. decreed
that ten entire days should be dropped out of the month of October. This
was called the change from Old to New Style."

"It was rather stupid," said Gus, "to shorten the pleasantest month in
the whole year. I would have clipped December or March."

"Please don't forget to tell us," said May, "how the months got their
names."

"The first six of them were called after the heathen deities, Janus,
Februus, Mars, Aphrodite, Maia, and Juno; July was named after Julius
Caesar, the inventor of leap-year; August after Augustus the Emperor. The
names of the last four months simply mean seventh, eighth, ninth, and
tenth."

"But," said Joe, "December is not the tenth month, nor is September the
seventh."

"That is true," said the Professor; "but those names are supposed to
have been given by Romulus, who arranged a year of only ten months, and
made it begin with March. His year only had 304 days in it, and was soon
found to be much too short. So the months of January and February were
added, and instead of being placed at the end, they came in some way to
stand at the beginning."

"Now please tell us about the names of the days of the week, and we will
not ask any more questions."

"They were called after the sun, moon, and five planets known to the
ancients, Mars, Mercury, Jupiter, Venus, and Saturn. You easily
recognize sun, moon, and Saturn, Tuesday, Thursday, and Friday are from
names given by some of the Northern tribes of Europe to Mars, Jupiter,
and Venus. Me