TERRESTRIAL MAGNETISM, ETC. 229 



to be movable round a vertical axis, perceived it 

 to turn into one particular direction when left 

 to itself, and who found that the positions thus 

 assumed were sensibly parallel when the sus- 

 pended magnet is carried about to different 

 places indoors or out-of-doors, near enough to 

 be within sight of one another, invented the 

 Mariner's Compass. There may have been several 

 independent inventors ; there can have been but 

 one first inventor. The efforts of historical in- 

 quirers have hitherto proved unavailing to fix 

 either time, place, or person for this invention, 

 not more remarkable for its definiteness as a 

 discovery than for its perennial utility to the 

 human race. 



It is generally believed that the compass was 

 known at an early date in China, and used as a 

 guide for travelling by land at a very early period 

 of the world's history. In the English translation 

 (London, 1736) of the Pere Duhalde's book on 

 China, in the Section entitled Annals of the 

 Chinese Monarchy r , a Chronological History of tJie 

 most Remarkable Events that happened diiring the 



