he was only a day's journey from home, Columbus was acquainted with such
stories as this, and also had the astronomical knowledge which almost
made him know that the world was round, "and, like a ball, goes spinning
in the air." The difficulty was to persuade other people that, because
of this roundness, it would be possible to attain Asia by sailing to the
West.

Now all the geographers of repute supposed that there was not nearly
so large a distance as there proved to be, in truth, between Europe and
Asia. Thus, in the geography of Ptolemy, which was the standard book
at that time, one hundred and thirty-five degrees, a little more than
one-third of the earth's circumference, is given to the space between
the extreme eastern part of the Indies and the Canary Islands. In fact,
as we now know, the distance is one hundred and eighty degrees, half the
world's circumference. Had Columbus believed there was any such immense
distance, he would never have undertaken his voyage.

Almost all the detailed knowledge of the Indies which the people of
his time had, was given by the explorations of Marco Polo, a Venetian
traveler of the thirteenth century, whose book had long been in the
possession of European readers. It is a very entertaining book now, and
may well be recommended to young people who like stories of adventure.
Marco Polo had visited the court of the Great Khan of Tartary at Pekin,
the prince who brought the Chinese Empire into very much the condition
in which it now is. He had, also, given accounts of Japan or Cipango,
which he had himself never visited. Columbus knew, therefore, that,
well east of the Indies, was the island of Cipango, and he aimed at that
island, because he supposed that that was the nearest point to Europe,
as in fact it is. And when finally he arrived at Cuba, as the reader
will see, he thought he was in Japan.