218 A SHORT HISTORY OF SCIENCE 



less remarkable. Tycho was destined to lay the foundation of modern 

 astronomy by a vast series of accurate observations made with the 

 largest and the finest instruments; it was the proud lot of Kepler to 

 deduce the laws of the planetary orbits from the observations of his 

 predecessors; while Galileo enjoyed the more dazzling honor of 

 discovering by the telescope new celestial bodies and new systems 

 of worlds. Brewster. 



Coming into a world still dominated by the Aristotelian tradi- 

 tion, Galileo is puzzled by the conflict between his own obser- 

 vations and the accepted theories, but firm and fearless in his 

 convictions, he eagerly and powerfully controverts the older notions, 

 incidentally gaining enemies as well as disciples. What those 

 accepted theories were may be exemplified by the following pas- 

 sages from a work of Daniel Schwenter (1585-1636), professor of 

 mathematics at Altdorf : 



'When a body falls it moves faster the nearer it approaches the 

 earth. The farther it falls the more power it possesses. For every- 

 thing which is heavy, hastens according to the opinion of philosophers 

 towards its natural place, that is the centre of the earth, just as man 

 returning to his fatherland becomes the more eager the nearer he 

 comes, and therefore hastens so much the more. Still another natural 

 cause contributes to this. The air which is parted by the falling ball, 

 hastens together again behind the ball and drives it always harder. 7 



If the Copernican theory were true, the bullet remaining two 

 minutes in the air would be left many miles behind by the revolv- 

 ing earth, a distance which the moving atmosphere could not 

 possibly carry it. The rainbow is "a mirror in which the human 

 understanding can behold its ignorance in broad day." The 

 powder drives the bullet in an oblique line to the highest point 

 of its path, then follows motion in an arc, finally, the natural 

 motion vertically downward. 



In his whole point of view and habit of mind Galileo embodied 

 the attitude and spirit of modern science. He was keenly alert 

 in observing, analyzing, and reflecting on natural phenomena, 

 eager and convincing in his expositions, sceptical and intolerant 



