Identity of Electricities. 



357 



put in circulation at each effort. It is doubtful whether any 

 common electrical machine has as yet been able to supply elec- 

 tricity sufficient in a reasonable time to cause true electro-che- 

 mical decomposition of water (330. 339. ), yet the current from 

 the torpedo has done it. The same high proportion is shown 

 by the magnetic effects (296. 371.J* These circumstances in- 

 dicate that the torpedo has power (in the way probably that 

 Cavendish describes,) to continue the evolution for a sensible 

 time, so that its successive discharges rather resemble those 

 of a voltaic arrangement, intermitting in its action, than those 

 of a Leyden apparatus, charged and discharged many times 

 in succession. In reality, however, there is no philosophical 

 difference between these two cases. 



360. The general conclusion which must, I think, be drawn 

 from this collection of facts is, that electricity, whatever may 

 be its source, is identical in its nature. The phaenomena in 

 the five kinds or species quoted, differ not in their character, 

 but only in degree ; and in that respect vary in proportion to 

 the variable circumstances of quantity and intensity* which can 

 at pleasure be made to change in almost any one of the kinds 

 of electricity, as much as it does between one kind and 

 another. 



Table of the experimental Effects common to the Electricities 

 derived from different Sources. 



* The term quantity in electricity is perhaps sufficiently definite as to 

 sense ; the term intensity is more difficult to define strictly. I am using the 

 terms in their ordinary and at present accepted meaning. 



