456 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. 



of this equality of action could not be understood whilst the definite action and evo- 

 lution of electricity (783. 869.) remained unknown. 



993. The superior decomposing power of a battery over a single pair of plates is 

 rendered evident in two ways. Electrolytes held together by an affinity so strong as 

 to resist the action of the current from a single pair, yield up their elements to the 

 current excited by many pairs ; and that body which is decomposed by the action of 

 one or of few pairs of metals, &c., is resolved into its ions the more readily as it is 

 acted upon by electricity urged forward by many alternations. 



994. Both these effects are, I think, easily understood. Whatever Intensity may 

 be, (and that must of course depend upon the nature of electricity, whether it con-, 

 sist of a fluid or fluids, or of vibrations of an ether, or any other kind or condition of 

 matter,) there seems to be no difficulty in comprehending that the degree of intensity 

 at which a current of electricity is evolved by a first voltaic element, shall be in- 

 creased when that current is subjected to the action of a second voltaic element, 

 acting in conformity and possessing equal powers with the first : and as the decom- 

 positions are merely opposed actions, but exactly of the same kind as those which 

 generate the current (917-)^ it seems to be a natural consequence, that the affinity 

 which can resist the force of a single decomposing action shall be unable to oppose the 

 energies of many decomposing actions, operating conjointly, as in the voltaic battery. 



995. That a body which can give way to a current of feeble intensity should give 

 way more freely to one of stronger force, and yet involve no contradiction to the 

 law of definite electrolytic action, is perfectly consistent. All the facts and also the 

 theory I have ventured to put forth, tend to show that the act of decomposition 

 opposes a certain force to the passage of the electric current ; and that this obstruc- 

 tion should be overcome more or less readily, in proportion to the greater o.r less 

 intensity of the decomposing current, is in perfect consistency with all our notions 

 of the electric agent. 



996. I have elsewhere (947.) distinguished the chemical action of zinc and dilute 

 sulphuric acid into two portions ; that which, acting effectually on the zinc, evolves 

 hydrogen at once upon its surface, and that which, producing an arrangement of the 

 chemical forces throughout the electrolyte present, (in this case water,) tends to take 

 oxygen from it, but cannot do so unless the electric current consequent thereon can 

 have free passage, and the hydrogen be delivered elsewhere than against the zinc. 

 The electric current depends altogether upon the second of these ; but when the 

 current can pass, by favouring the electrolytic action it tends to diminish the former 

 and increase the latter portion. 



997. It is evident, therefore, that when ordinary zinc is used in a voltaic arrange- 

 ment, there is an enormous waste of that power which it is the object to throw into 

 the form of an electric current ; a consequence which is put in its strongest point of 

 view when it is considered that three ounces and a half of zinc, properly oxydized, 

 can circulate enough electricity to decompose nearly one ounce of water, and cause 



