in the handwriting of Columbus shows how the great navigator's imagination was fired by these accounts and explains his conviction, when he had reached the West Indies, that they were outlying parts of the Great Khan's dominions.

Belief that the earth was a sphere

The theory that the earth was a sphere was perfectly familiar to men of learning in the Middle Ages. Aristotle held it in the fourth century, B.C., and called attention to the fact that the earth's shadow on the moon in eclipses was always circular, and that stars visible in Egypt fell below the horizon of one traveling northward. Later Greek and Roman writers held the same view, and that the idea was familiar to the educated classes of Italy is clearly shown by the fact that Dante in the Divine Comedy places his Inferno in the center of a spherical earth. It should be remembered, however, that the educated class then was far more limited than it is to-day and that the belief of the masses was in a flat earth, a view to which the Church on Biblical grounds lent the weight of its authority.

Columbus, in common with other navigators, appears to have accepted the scientific view without serious question: "I have always read," said he, "that the world, comprising the land and the water, is spherical, as is testified by the investigations of Ptolemy and others, who have proved it by the eclipses of the moon and other observations made from east to west, as well as by the elevation of the pole from north to south." Still there were no convincing geographical data to support this theory, and ignorance of the law of gravitation, as expounded by Sir Isaac Newton two centuries later, made very real to the ignorant sailor the now absurd fear that if a ship should sail too far down the sides of the earth it would be impossible to sail back to the top.

The enthusiasm which inspired men to undertake perilous voyages of discovery and exploration during the fifteenth century was one of the many expressions of the new spirit