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THE POPULAR SCIENCE MONTHLY 



GALIIJilO. 



sink while light ones arise. All his statements relating to mechanics 

 are erroneous and some are positively childish. 



The first real student of mechanics was Archimedes (287-312 B.C.) 

 To him we owe the foundations of the science. For example, to him 

 we owe the theory of the lever, from which he developed the idea of the 

 center of gravity. He was especially interested in the subject of hydro- 

 statics, and established principles that are of universal application 

 to-day. His practical applications are best illustrated in the engines 

 of war which he devised to aid in the defense of Syracuse. So effective 

 were these that the Romans took the city not by assault but by starva- 

 tion. For fifteen hundred years thereafter practically no advance was 

 made. In 1462 the Turks took Constantinople, and fugitive Greeks 



