94 GALILEO AND HIS JUDGES. 



persons to have been discovered by Galileo, and it 

 appears that he stated it fully and clearly ; but he 

 can scarcely be said to be the discoverer of it, as it 

 had been known to others, and had even at least as 

 exemplified in the case of the lever been noticed by 

 Aristotle. There is, however, no doubt that Galileo 

 was the greatest man of his day in mechanical know- 

 ledge, whether we attribute more or less weight to 

 the light he threw on particular details. 



In astronomy he was necessarily a discoverer, for the 

 all-important reason that, as already stated, he was 

 the first man that ever used the telescope for investi- 

 gating the phenomena of the heavens. He thus saw 

 what no one previously had seen,* the satellites of 

 Jupiter, the spots on the Sun, and the moon-like 

 phases of the planet Venus, besides the greatly 

 increased number of stars, so many of which are 

 invisible to the naked eye. 



The first-mentioned of these discoveries, that of 

 the satellites of Jupiter, seems to have created an 

 immense sensation among the savants of that day. 

 It suggested that the theories of Ptolemy were any- 

 thing but complete or correct, and yet it proved 

 nothing, excepting against those d priori reasoners, 

 who would not believe that a body round which a 

 moon circulated could itself be in motion ; but the 

 phases of Venus were simply conclusive against the 



* The spots on the Sun were seen at about the same period of 

 time by Fabricius and by Father Scheiner, a Jesuit, as already 

 mentioned. 



