OTTO VON GUERICKE. 389 



of Brandenburg, and lie had other titles bespeaking great 

 consideration. But, at the present time, a couple of cen- 

 turies later, the moths have eaten all these dignities and 

 we know Otto von Guericke best as one of the first and 

 greatest of the electrical discoverers. 



Now, we have to find out what Monconys saw. 



Otto von Guericke 1 was Burgomaster of Magdeburg for 

 thirty-five years. He was a many-sided man. He had 

 studied law at L,eipsic, Helmstadt and Jena, and mathe- 

 matics at Leyden, and had travelled through France and 

 England. He had established himself as an engineer at 

 Erfurt, when the attractions of an official career proved 

 more potent than those of his profession, and he entered 

 political life in 1627 as an alderman of his native town. 

 But he conld not divorce himself from his interest in phy- 

 sical science; and so, throughout his long public service, 

 he made work in his laboratory his relaxation and his 

 play: just as President Jefferson found pleasure in experi- 

 menting upon the conduction of heat through fabrics amid 

 the engrossing cares of the White House, or as Charles II., 

 discovered in physical experiments conducted in his closet 

 at Whitehall, a welcome relief from the feverish excite- 

 ments and frivolity of his court. 



In the history of pneumatics, von Guericke stands in the 

 highest place. He invented the air-pump in 1650, and 

 discovered that in a vacuum animals cannot exist, and all 

 bodies fall with equal rapidity. He recognized that gases 

 have weight, and by means of the u Magdeburg hemi- 

 spheres," already alluded to, he showed how great the 

 force due to pressure exerted by the air, by comparing it 

 with the contrary pulling strain of horses. He invented 

 the air-balance and the anemoscope, and, by such means, 

 weighing the air, he was enabled to make his astonishing 



Hoffman: Otto von Guericke. Magdebourg, 1874. Paschius: De In- 

 mtis, vii., 29. Fontenelle : Eloges Hist, des Acad., vol. ii. 



