gun that onslaught upon the old
Aristotelian ideas which he was to continue throughout his life. At the
famous leaning tower in Pisa, the young iconoclast performed, in the
year 1590, one of the most theatrical demonstrations in the history
of science. Assembling a multitude of champions of the old ideas, he
proposed to demonstrate the falsity of the Aristotelian doctrine that
the velocity of falling bodies is proportionate to their weight. There
is perhaps no fact more strongly illustrative of the temper of
the Middle Ages than the fact that this doctrine, as taught by the
Aristotelian philosopher, should so long have gone unchallenged. Now,
however, it was put to the test; Galileo released a half-pound weight
and a hundred-pound cannon-ball from near the top of the tower, and,
needless to say, they reached the ground together. Of course, the
spectators were but little pleased with what they saw. They could not
doubt the evidence of their own senses as to the particular experiment
in question; they could suggest, however, that the experiment involved
a violation of the laws of nature through the practice of magic. To
controvert so firmly established an idea savored of heresy. The young
man guilty of such iconoclasm was naturally looked at askance by the
scholarship of his time. Instead of being applauded, he was hissed, and
he found it expedient presently to retire from Pisa.

Fortunately, however, the new spirit of progress had made itself felt
more effectively in some other portions of Italy, and so Galileo found a
refuge and a following in Padua, and afterwards in Florence; and while,
as we have seen, he was obliged to curb his enthusiasm regarding the
subject that was perhaps nearest his heart--the promulgation of the
Copernican theory--yet he was permitted in the main to carry on his
experimental observations unrestrained. These experiments gave him a
place of unquestioned authority among his contemporaries, and they have
transmitted his name to posterity as that of one of the greatest of
experimenters and the virtual founder of modern mechanical science. The
experiments in question range over a wide field; but for the most part
they have to do with moving bodies and with questions of force, or, as
we should now say, of energy. The experiment at the leaning tower showed
that the velocity of falling bodies is independent of the weight of the
bodies, provided the weight is sufficient to overcome the resistance
of th