ON SOME CHEMICAL AGENCIES OF ELECTRICITY. 55 



such very low intensity* water is an insulating- body : every Mode of action 

 copper plate consequently produces by induction an increase w ith experi- 6> 

 oi" positive electricity upon the opposite zinc plate; and mental eluci- 

 every zinc plate an increase of negative electricity on the atlons * 

 opposite copper plate: and the intensity increases with the 

 number, and the quantity with the extent of the series. 



When a communication is made between the two extreme 

 points, the opposite electricities tend to annihilate each 

 other; and if the fluid medium could be a substance inca- 

 pable of decomposition, the equilibrium, there is every rea- 

 son to believe, would be restored, and the motion of the 

 electricity cease. But solution of muriate of soda being 

 composed of two series of elements possessing opposite elec- 

 trical energies, the oxigen and the acid are attracted by the 

 zinc, and the hidrogen and the alkali by the copper. The 

 balance of power is momentary only ; for solution of zinc is 

 formed, and the hidrogen disengaged. The negative energy 

 of the copper and the positive energy of the zinc are conse- 

 quently again exerted, enfeebled only by the opposing 

 energy of the soda in contact with the copper, and the pro- 

 cess of electroinotion continues, as long as the chemical 

 changes are capable of being carried on. 



This theory in some measure reconciles the hypothetical 

 principles of the action of the pile adopted by its illustrious 

 inventor, with the opinions concerning the chemical origin of 

 Galvanism, supported by the greater number of the British 

 philosophers, and it is confirmed and strengthened by many 

 lacts and experiments. 



Thus the Voltaic pile of 20 pairs of plates of copper and * 



zinc exhibits no permanent electromotive power when the 

 connecting fluid is water free from air*; for this substance 

 does not readily undergo chemical change, and the equili- 

 brium seems to be capable of being permanently restored 

 through it. Concentrated sulphuric acid, which is a much 

 more perfect conductor, is equally inefficient, for it has little 

 action upon zinc, and is itself decomposed only by a ver/ 

 strong power. Piles, containing as their fluid element ei- 



* The experiments proving this fact, and the other analogous tacts la 

 this page, may be seen detailed in Nicholson's Journal, 4to, Vol. IV, 

 I and.'>94; and Phil. Mag. Vol. X, p. 40. 



ther 



