Finding these cattle, he also heard the same cry of people calling cattle, which he had heard in the extreme East, and now learned, for the first time, that he had gone round the world on foot, to turn and come back by the same route, when 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.