race of savages, notably the American Indians. On the other hand,
one is inclined to give credence to almost any story of the breadth of
knowledge of the man who came so near anticipating Hutton, Lyell, and
Darwin in his interpretation of the geological records as he found them
written on the rocks.

It is in this field of geology that Leonardo is entitled to the greatest
admiration by modern scientists. He had observed the deposit of fossil
shells in various strata of rocks, even on the tops of mountains, and he
rejected once for all the theory that they had been deposited there by
the Deluge. He rightly interpreted their presence as evidence that
they had once been deposited at the bottom of the sea. This process
he assumed bad taken hundreds and thousands of centuries, thus tacitly
rejecting the biblical tradition as to the date of the creation.

Notwithstanding the obvious interest that attaches to the investigations
of Leonardo, it must be admitted that his work in science remained
almost as infertile as that of his great precursor, Bacon. The really
stimulative work of this generation was done by a man of affairs, who
knew little of theoretical science except in one line, but who pursued
that one practical line until he achieved a wonderful result. This man
was Christopher Columbus. It is not necessary here to tell the trite
story of his accomplishment. Suffice it that his practical demonstration
of the rotundity of the earth is regarded by most modern writers as
marking an epoch in history. With the year of his voyage the epoch of
the Middle Ages is usually regarded as coming to an end. It must not be
supposed that any very sudden change came over the aspect of scholarship
of the time, but the preliminaries of great things had been achieved,
and when Columbus made his famous voyage in 1492, the man was already
alive who was to bring forward the first great vitalizing thought in
the field of pure science that the Western world had originated for more
than a thousand years. This man bore the name of Kopernik, or in its
familiar Anglicized form, Copernicus. His life work and that of his
disciples will claim our attention in the succeeding chapter.

IV. THE NEW COSMOLOGY--COPERNICUS TO KEPLER AND GALILEO

We have seen that the Ptolemaic astronomy, which was the accepted
doctrine throughout the Middle Ages, taught that the earth is round.
Doubtless there was a popular opinion current which regarded the earth