SO MEMOIR OF GALILEO. 



of Padua ; with an income of 180 florins. The death of 

 his father having burdened Galileo with the family, he had 

 to apply himself here as at Pisa, to private teaching. Not- 

 withstanding his public and private duties, however, he still 

 found leisure to make several discoveries and inventions, 

 which were circulated in manuscript amongst his friends. 

 Some of these abused the confidence reposed in them, and 

 published several of Galileo's inventions as their own. 



The doctrines of Copernicus, regarding the stability of the 

 sun and the revolution of the planets, were the subject of 

 disputation among the learned in the time of Galileo. He 

 early became a convert to the new doctrines, and believed 

 in them even at the time he was teaching the opposite or 

 Ptolemaic system, which regarded the earth as stationary, 

 and the sun a revolving body. Shortly after he went to 

 Padua, he published a treatise on the sphere, in which the 

 system of Ptolemy was supported by the very arguments 

 which he afterward ridiculed. It is rather considered, how- 

 ever, that it was some time after the publication of this 

 treatise that Galileo changed his opinions. About this time 

 he commenced a correspondence with Kepler, the German 

 astronomer, which continued till his death. 



In 1593, he contracted a chronic disorder, from inadvert- 

 ently sleeping at an open window, which afflicted him at in- 

 tervals during the rest of his life. At this time, Galileo's 

 reputation as a philosopher was widely extended all over 

 Europe, and many of the nobility became his pupils. His 

 first engagement as professor at Padua was for six years. 

 On the expiry of this term, he was re-engaged for other six 

 years, at an advanced salary of 320 florins. The first im- 

 portant discovery of Galileo was, that the vibrations of a 

 pendulum are performed in equal times, whatever be the size 

 of the arc described, within certain limits. In 1604, a new 

 star was discovered by astronomers in the constellation of 

 Ophiucus, and formed the subject of much speculation By 



