GALILEO GALILEI. 9 



generations that have come and gone since these 

 two men lived and wrote and suffered. 



At Padua, Galileo soon attracted great numbers 

 to his class-room. Often a thousand gathered to 

 hear his lectures, and when the hall was too 

 cramped, he spoke to the people in the open air. 

 He was above the middle height, well proportioned, 

 with cheerful countenance, witty in conversation, 

 and enthusiastic in his manner. So learned that 

 he could repeat by heart much of the works of 

 Virgil, Ovid, Horace, and Seneca ; he was yet mod- 

 est and unassuming, saying that he never met a 

 man so ignorant but that something might be 

 learned from him. 



He labored incessantly. He wrote treatises on 

 Fortifications, on Mechanics, on Gnomonics, on the 

 laws of motion, on the celestial globe, which were 

 copied by his pupils, and sent by them far and 

 wide over Europe. He took a workman into his 

 family, and began to superintend the making of the 

 compass which he had invented, and the thermo- 

 scope, or heat indicator, which led in later years to 

 the thermometer. His experiment was made by a 

 " glass bottle about the size of a hen's egg, the 

 neck of which was two palms long, and as narrow 

 as a straw. Having well heated the bulb in his 

 hands, he placed its mouth in a vessel containing a 

 little water, and withdrawing the heat of his hand 

 from the bulb, instantly the water rose in the neck, 

 more than a palm above the level of the water in 

 the vessel." 



