44 HISTORY OF GALVANISM. 



by Biot, who wrote a memoir, the principal object 

 of which was to illustrate the relative action of 

 the different kinds of apparatus, and to discover 

 the cause on which this difference depends. Elec- 

 tricity is known to be discharged by points, and 

 to be retained by extensive surfaces ; and from this 

 circumstance he conceives, that the smaller the 

 plates are, the more rapid will be the circulation 

 of the fluid ; large plates furnish a greater quan- 

 tity of the fluid, but it is less rapid in its motion ; 

 smaller plates, on the contrary, furnish less fluid, 

 but it passes with more rapidity through the 

 different parts of the apparatus. Hence what was 

 spoken of by Nicholson and others, as constituting 

 the intensity of the fluid, is resolved by Biot into 

 Different the velocity of its motion. The different opera- 

 tions of the pile are differently affected by these 

 two properties. The taste, the flash, and the shock, 

 exist nearly in the same degree, and all depend 

 principally upon the velocity ; while the combus- 

 tion of the metals is more influenced by the 

 quantity of the electricity. The electrical attrac- 

 tions also depend upon the quantity of fluid, 

 and are therefore more perceptible when large 

 plates are used. It is observed that a pile com- 

 posed of small plates affords very pungent shocks, 

 but is more quickly exhausted. It was before 

 stated, that Biot had perceived the pile to deoxi- 

 date a portion of the air in which it was confined ; 

 and he now informs us, that the effect was pro- 

 duced more rapidly when the ends of the pile were 



