latter part of the fifteenth century, however, there is evidence
of a renaissance of science no less than of art. The German
Muller became famous under the latinized named of Regio Montanus
(1437-1472), although his actual scientific attainments would
appear to have been important only in comparison with the utter
ignorance of his contemporaries. The most distinguished worker of
the new era was the famous Italian Leonardo da Vinci--a man who
has been called by Hamerton the most universal genius that ever
lived. Leonardo's position in the history of art is known to
every one. With that, of course, we have no present concern; but
it is worth our while to inquire at some length as to the famous
painter's accomplishments as a scientist.

From a passage in the works of Leonardo, first brought to light
by Venturi,[1] it would seem that the great painter anticipated
Copernicus in determining the movement of the earth. He made
mathematical calculations to prove this, and appears to have
reached the definite conclusion that the earth does move--or what
amounts to the same thing, that the sun does not move. Muntz is
authority for the statement that in one of his writings he
declares, "Il sole non si mouve"--the sun does not move.[2]

Among his inventions is a dynamometer for determining the
traction power of machines and animals, and his experiments with
steam have led some of his enthusiastic partisans to claim for
him priority to Watt in the invention of the steam-engine. In
these experiments, however, Leonardo seems to have advanced
little beyond Hero of Alexandria and his steam toy. Hero's
steam-engine did nothing but rotate itself by virtue of escaping
jets of steam forced from the bent tubes, while Leonardo's