ANALYSIS OF THE GALVANIC PILE. £5(J 



*' with such a minute quantity of electric fluid set in mo- 

 •' tion by the pile, the shock and chemical effects are pro- 

 '* duced, while they require a very great quantity of the 

 ■• s-dme fluid, when set in motion by any of the other known 

 " electric apparatuses?" Being arrived at the general fact 

 above stated, that these effects are never produced but by 

 the decomposition of some particles of the electric fluid, oc- 

 casioned by an excess of density, in darting from one point 

 of a conductor to another, the answer to the connected 

 questions is obvious: the modification undergone by the elec- 

 tric fluid in pervading this pile is such, that some of its 

 particles are decomposed by a very small increase of den- 

 sity, when a conductor is interrupted. We have an analogy 

 of the general case of more easy decomposition of compounds 

 by previous modifications of the latter, in the processes of 

 smelting ores, for obtaining metals or reguli from them; 

 for an easy separation of the ingredient of the latter must 

 be prepared, by substruction or addition of other ingredi- 

 ents, and often by both. And as we see, that the calcina- For the shock 



tion by an acid is necessary to produce the shock, it is pro- so:rie ele ™ent 

 i 1 , , i t %t ,- e T i • n .7. ,. • added to the 



bable, that the modification 01 the electric fluid in this case is electric fluid. 



the addition of some element. 



I come now to the second of the above questions: "What 26. question. 

 " is the cause of a motion of the electric fluid in the pile ? 

 " either producing, or not producing, the shock and che- 

 " mical effects in the circuit?" The first point to be con- 

 sidered with respect to this question concerns the nature of 

 the modifications reciprocally produced by zinc and copper 

 upon each other, when brought into contact. It is gene- 

 rally said, that, in this case, zinc becomes positive, and 

 copper negative. But these expressions, according to what 

 has been stated above, cannot relate to the expansive power \ 

 of the electric fluid', for, between two bodies in mutual 

 contact, such a poivcr must be in equilibrium; therefore 

 these expressions must relate to density, such as I have de- 

 fined it. Let us now attend to the experiments. 



These trials are usually made with disks of zinc and cop- Contacts f 

 per (or brass) having an insulating handle in their centre, ziuc & copper, 

 like the plate of an electrophorus, and with the help of the 

 condenser; thus, one of the disks being held on the hand 

 the other is first laid upon it, then brought, by its insulating - 



S 2 handle, 



