CHAP. 7. OP ELECTRICITY. 205 



CHAPTER VII. 



OF ELECTRICITY. 



IF we look back into the history of any 

 branch of science, we shall observe, that in the 

 progress of its developement, men have, from 

 time to time, introduced a number of different 

 hypotheses to explain the cause of the com- 

 plicated phaenomena which they observed; 

 which hypotheses have obtained credit for a 

 while, and have reigned triumphant ; but be- 

 fore long they have faded away, from being 

 found incapable of explaining more recently 

 discovered facts, or have been overthrown by 

 others of greater pretensions to credit. From 

 time immemorial, systems of philosophy have 

 mutually overthrown and succeeded each 

 other ; and many, which have been rejected by 

 philosophers of antiquity, have been brought 

 into vogue again, under some new dress, by 

 subsequent generations : and thus, in the re- 

 volutions of science, systems have alternately 

 decayed and flourished at remote distances of 

 time. Electricity affords a striking example of 



