GALILEO AND THE NEW PHYSICS 



spects scarcely less important than his own. These 

 men are the Dutchman Stevinus, who must always 

 be remembered as a co-laborer with Galileo in the 

 foundation of the science of dynamics, and the Eng- 

 lishman Gilbert, to whom is due the unqualified praise 

 of first subjecting the phenomenon of magnetism to a 

 strictly scientific investigation. 



Stevinus was born in the year 1548, and died in 1620. 

 He was a man of a practical genius, and he attract- 

 ed the attention of his non-scientific contemporaries, 

 among other ways, by the construction of a curious 

 land-craft, which, mounted on wheels, was to be pro- 

 pelled by sails like a boat. Not only did he write a 

 book on this curious horseless carriage, but he put his 

 idea into practical application, producing a vehicle 

 which actually traversed the distance between Sche- 

 veningen and Pet ton, with no fewer than twenty-seven 

 passengers, one of them being Prince Maurice of Orange. 

 This demonstration was made about the year 1600. It 

 does not appear, however, that any important use was 

 made of the strange vehicle ; but the man who invent- 

 ed it put his mechanical ingenuity to other use with 

 better effect. It was he who solved the problem of 

 oblique forces, and who discovered the important hy- 

 drostatic principle that the pressure of fluids is pro- 

 portionate to their depth, without regard to the shape 

 of the including vessel. 



The study of oblique forces was made by Stevinus 

 with the aid of inclined planes. His most demonstra- 

 tive experiment was a very simple one, in which a 

 chain of balls of equal weight was hung from a tri- 

 angle ; the triangle being so constructed as to rest on a 



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