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A SHORT HISTORY OF SCIENCE 



Leonardo da Vinci likens a scientific conquest to a military victory 

 in which theory is the field marshal, experimental facts the soldiers. 

 The philosophers who preceded Galileo had, in the main, been trying 

 to fight battles without soldiers. Crew. 



A PIONEER IN MECHANICS. STEVINUS. Even before Galileo, 

 Stevinus of Bruges (1548-1620), a man who thought independently 

 on mechanical problems, made the first really important advances 

 since Archimedes, eighteen centuries earlier. Besides engaging 

 in mercantile pursuits he was quartermaster-general of the 

 Dutch army, and an authority on military engineering. He was 

 influential in improving methods of public statistics and account- 

 ing, and advocated decimal weights and measures. Appreciating 

 the possibilities of the decimal fraction he asserted (1585) that 

 fractions are quite superfluous, and every computation can be 

 made with whole numbers, but he did not realize the simplest 

 notation. The honor of this great invention he shares with Biirgi 

 of Cassel. Another of his inventions was a sailing carriage carry- 

 ing 28 people and outstripping horses. 



In a treatise on Statics and Hydrostatics (1586) he introduced 

 comparatively new and powerful geometrical methods for dealing 



with mechanical problems. 

 Among the most interesting is 

 his discussion of the inclined 

 plane by means of an endless 

 chain hanging freely over a tri- 

 angle with unequal sides. Ex- 

 cluding the inadmissible hy- 

 pothesis of perpetual motion, 

 the uniform chain must be in 

 equilibrium in any position. 

 The hanging portion is by itself 

 in equilibrium, therefore the 

 two inclined sections must bal- 

 ance each other, and either 

 would be balanced by a verti- 

 stevinus' Triangle. cal force corresponding to the 



