206 Things not generally Known. 



monly used, especially by our most recent and comprehensive writers. 

 The Voltaic pile was a more important step in the history of electricity 

 than the Ley. I en jar had been Hist. Ind. Sciences, vol. lii. 



No one who wishes to judge impartially of the scientific history of 

 these times and of its leaders, will consider Galvani and Volta as equals, 

 or deny the vast superiority of the latter over all his opponents or fellow- 

 workers, more especially over those of the Bologna s hool. We shall 

 scarcely again lind in one man gifts so rich and so calculated for research 

 as were combined in Volta. He possessed that " incomprehensible 

 talent," as Dove has called it, for separating the essential from the im- 

 material in complicated phenomena ; that boldness of invention which, 

 must precede experiment, controlled by the most strict and cautious 

 mode of manipulation ; that unremitting attention which allows no cir- 

 cumstance to pass unnoticed ; lastly, with so much acuteness, so much 

 simplicity, so much grandeur of conception, combined with such depth 

 of thought, he had a hand which was the hand of a workman. Jame- 

 son's Journal, No. 106. 



THE VOLTAIC BATTERY AND THE GYMNOTUS. 



" We boast of our Voltaic Batteries," says Mr. Smee. " I 

 should hardly be believed if I were to say that I did not feel 

 pride in having constructed my own, especially when I consider 

 the extensive operations which it has conducted. But when I 

 compare my battery with the battery which nature has given 

 to the electrical eel and the torpedo, how insignificant are hu- 

 man operations compared with those of the Architect of living 

 beings ! The stupendous electric eel in the Polytechnic Insti- 

 tution, when he seeks to kill his prey, encloses him in a circle ; 

 then, by volition, causes the voltaic force to be produced, and 

 the hapless creature is instantly killed. It would probably re- 

 quire ten thousand of my artificial batteries to effect the same 

 object, as the creature is killed instanteron receiving the shock. 

 As much, however, as my battery is inferior to that of the elec- 

 tric fish, so is man superior to the same animal. Man is en- 

 dowed with a power of mind competent to appreciate the force 

 of matter, and is thus enabled to make the battery. The eel 

 can but use the specific apparatus which nature has bestowed 

 upon it." 



Some observations upon the electric current around the 

 gymnotus, and notes of experiments with this and other electric 

 fish, will be found in Things not generally Known, p. 199. 



VOLTAIC CURRENTS IN MINES. 



Many years ago, Mr. R. W. Fox, from theory entertaining 

 a belief that a connection existed between voltaic action in the 

 interior of the earth and the arrangement of metalliferous veins, 

 and also the progressive increase of temperature in the strata as 

 we descend from the surface, endeavoured to verify the same 

 from experiment in the mine of Huel Jewel, in Cornwall. His 



