58 HISTORY OF GALVANISM. 



to the former. Biot drew up a candid and ju- 

 dicious memoir, in which he compares the merits of 

 the two opinions, and endeavours to show how far 

 either of them is supported by acknowledged facts. 

 Electricity, he observes, is certainly excited, but it 

 is not certain whether we ought to regard it as 

 cause or effect. He proceeds to inquire whether 

 the action of the pile depends upon the oxidation 

 of one of the metals, upon their electric operation, 

 or upon the two causes in conjunction. The first 

 supposition, he says, is certainly not true, because 

 Volta has proved that metals produce electricity by 

 mere contact, without any oxidation taking place, 

 and his experiments likewise tend to show that 

 the fluid merely performs the part of a conductor, 

 because the electrometer is equally affected whe- 

 ther water or acid be employed; but M. Biot doubts 

 the accuracy of this experiment. It is admitted 

 that the increase of electricity is in proportion to 

 the oxidation of one of the metals ; but this cir- 

 cumstance does not prove that these actions stand 

 to each other in the relation of cause and effect, 

 it only shows that electricity renders bodies more 

 oxidable. He performed a set of comparative ex- 

 periments on the effect of different fluids being 

 interposed between the metals, and by employing 

 the electrical balance as a measure of the quantity 

 of electricity that was liberated, he finds that it 

 is much influenced by the nature of the fluid. The 

 following is supposed to be the order in which the 

 fluids have the power of exciting the action of 



