THE PATH OF EVOLUTION 



named Sagredo, a man of culture and of high stand- 

 ing, obtained for the young mathematician the Chair 

 of that Science in Padua for the term of six years. 

 In recognition of the kindness, Galileo gave their 

 names to the personages in his dialogues who sus- 

 stained the new and true philosophy. During this 

 time he invented the thermometer and made some 

 other minor inventions. At the expiration of his 

 term at the University the Senate again elected him 

 to a second period of six years, with an increased 

 salary. The sudden appearance of a new star in the 

 constellation Serpentarius enabled Galileo to demon- 

 strate that its position was far beyond the elementary 

 sphere in which alone according to the philosophy 

 of Aristotle changes of any kind were possible. 

 In 1606 his professorship was again renewed. 



In 1609 it was rumored that the Count Maurice 

 of Nassau had been presented by a native of Middel- 

 burg, Holland, with an instrument that made distant 

 objects seem to be much closer and nearer to hand 

 than they really were. This was all that he could 

 learn about the instrument. From this information 

 Galileo proceeded to ascertain how such a thing was 

 possible, by experimenting with spherical glasses in 

 various shapes. After some attempts with such as 

 he had at hand, he succeeded in his efforts, and a few 

 days after presented to the Senate several of his new 



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