296 On the Pheenomena of the Electrophorus. 



cover as charges for separate jars ; the cover when raised 

 charging like the prime conductor of an ordinary electrical 

 machine, and when set on the cake charj^ing it like the 

 rubber. This caused the inventor, M. Volta, to give it 

 the name of electrophorus. 



" S. It" the sole be insulated before the cover is imposed, 

 the spark obtained from the cover is not of that cutting kind 

 that it was before; but the same shock will be felt if both 

 cake and cover be touched together." 



I understand this to iniply, that when insulated the elec- 

 tricity of the cover becomes positive, or, instead of receiv- 

 ing a spark from the finger, yields one to it : if this be 

 meant, it is contrary to fact. (See No. 9, in table of expe- 

 riments.) If the sole be not insulated, the cover after im- 

 posing becomes weakly positive, (see No. 7,) and the spark 

 between the cover and finiier is scarcely perceptible. 



" 9. If the cover be raised to a considerable height, the 

 sole will be found electrical, and its electricity is that of 

 the cake, and not the same as the cover. (See No. 10.) 



*' 10. After touching both sole and cover, if the cover 

 be raised and again set down without touching it while aloft, 

 the wliole is again inactive. 



"11. If both sole and cover be made inactive when in 

 contact with the cake, they show opposite electricities when 

 separated, the sole having the electricity of the cake. 



" 12. If both sole and cover be made inactive when se- 

 parate, they both show the opposite to llre-cleetricity of the 

 cake when joined." 



I have sometimes observed each plate when thus situated 

 assume the same electricity as the cake, but never both of 

 them the opposite state. 



These are the material facts upon this subject stated in 

 the Supplement to the Encijclopcedia Briton/iica, which is 

 followed by an ingenious attempt to account for them in 

 conformitv to the principles of the ^Epinian theory. Some 

 of the data appear to me to be assumed without sufficient 

 proof: but as in my former paper, to which this is a sup- 

 plement, I declined the consideration of that theorv, and 

 confined mvseif to what is called the Franklinian hypothesis, 

 I shall pursue the same course on the present occasion, 

 especiallv ;:s the theory above alluded to is involved in a 

 great deal of maUicmatical and algebraical formuUe ; and I 

 cannot pretend to have studied it with sufficient attention 

 to do justice to the reasoning brought forward in its sup- 

 port, or represent with perspicuity tlic explanations which 

 U offers. 



I shall 



