A HISTORY OF SCIENCE 



instead an open field, to which were invited Emperor 

 Ferdinand III., and all the princes of the Diet at Ratis- 

 bon. When they were assembled he produced two 

 hollow brass hemispheres about two feet in diameter, 

 and placing their exactly fitting surfaces together, pro- 

 ceeded to pump out the air from their hollow interior, 

 thus causing them to stick together firmly in a most 

 remarkable way, apparently without anything holding 

 them. This of itself was strange enough; but now the 

 worthy burgomaster produced teams of horses, and 

 harnessing them to either side of the hemispheres, at- 

 tempted to pull the adhering brasses apart. Five, ten, 

 fifteen teams thirty horses, in all were attached ; but 

 pull and tug as they would they could not separate 

 the firmly clasped hemispheres. The enormous press- 

 ure of the atmosphere had been most strikingly de- 

 monstrated. 



But it is one thing to demonstrate, another to con- 

 vince; and many of the good people of Magdeburg 

 shook their heads over this "devil's contrivance," and 

 predicted that Heaven would punish the Herr Burgo- 

 master, as indeed it had once by striking his house with 

 lightning and injuring some of his infernal contrivances. 

 They predicted his future punishment, but they did 

 not molest him, for to his fellow-citizens, who talked 

 and laughed, drank and smoked with him, and knew 

 him for the honest citizen that he was, he did not seem 

 bewitched at all. And so he lived and worked and 

 added other facts to science, and his brass hemispheres 

 were not destroyed by fanatical Inquisitors, but are 

 still preserved in the royal library at Berlin. 



In his experiments with his air-pump he discovered 



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