26 MECHANICS. 



philosophy, was performed from the top of the leaning 

 tower of Pisa. Galileo was a philosophical teacher, and, 

 being a man who thought for himself, soon discovered, by 

 reasoning, the errors tl)at had been received without a 

 doubt for more than twenty centuries. All the learning 

 of the acre and the wisdom of the universities were asjainst 

 him, and in favor of this time-honored error, the truth of 

 which no one had ever thought of submitting to experi- 

 ment. The hour of trial arrived, when he, an obscure 

 young man, 'stood nearly alone on one side, while the 

 multitude, with all the power and xjonfessed knowledge 

 of the age, were on the other. 



The balls to be employed were carefully weighed and 

 scrutinized to detect deception, and the parties were satis- 

 fied. The one ball was exactly twice the weight of the 

 other. The followers of Aristotle maintained that when 

 the balls were dropped from the top of the tower, the 

 heavy one would reach the ground in exactly half the 

 time employed by the lighter ball. Galileo asserted that 

 the weights of the balls would not affect their velocities, 

 and that the times of descent would be equal. The balls 

 were conveyed to the summit of the lofty tower the 

 crowd assembled round the base the signal was given 

 the balls were dropped at the same instant, and swiftly 

 descending, at the same moment struck the earth. Again 

 and again the experiment was repeated with unifoim 

 results. Galileo's triumph was complete not a shadow 

 of doubt remained; but, instead of receiving the con- 

 gratulations of honest conviction, private interest, the loss 

 of place, and the mortification of confessing false teach- 

 ing, proved too strong for the candor of his adversaries. 

 They clung to their former opinions with the tenacity of 

 despair, and he was driven from Pisa.* 



*Milcbeir8 Lectures. 



