Prof. Faraday on Electric Conduction. 99 



degrees, i. e. without the accompaniment of any chemical change 

 within them. The first kind of conduction is distinguished as 

 the electrolytic, the transference of the electric force ajipearing 

 to be essentially associated with the chemical changes which 

 occur; the second kind may be called conduction projjer, and 

 there the act of conduction leaves the body ultimately as it found 

 it. Electrolytic conduction is closely associated with the liquid 

 state, and with the compound nature and chemical proportions 

 of the bodies in which it occurs, and it is considered as varying 

 iu degree {i. e. in facility) with the affinities of the constituents 

 belonging to these bodies; there are, however, other circum- 

 stances which evidently, and indeed very strongly, affect the 

 readiness of transfer, such as temperature, the presence of ex- 

 traneous matters, &c. Conduction proper differs as to facility 

 by degrees so far apart, that that quantity of electricity which 

 could pass through a hundred miles of one substance, as copper, 

 in an inappreciably small portion of time, would require ages to 

 be transmitted through the like length of another substance, as 

 shell-lac ; and yet the copper with its similars offers resistance 

 to conduction, and the lac and its congeners conduct. 



The progress and necessities of science have rendered it im- 

 portant -o-ithin the last three or four years, and especially at the 

 present moment, that the question " whether an electrolyte has 

 any degree of conduction proper" should be closely considered, 

 and the experiments which are fitted to probe the question have 

 been carried to a very high degree of refinement. Buff*, by 

 employing the electric machine and WoUaston terminals, i. e. pla- 

 tinum wires sealed into glass tubes, and hanng the ends only 

 exposed, has decomposed water by a quantity of electricity so 

 small that it required four hours to collect gas enough to fill a 

 little cylinder only one-tenth of an inch in diameter, and one- 

 fifth of an inch in length ; yet the decomposition was electrolytic 

 and polar, and therefore the conduction was electrolytic also. 

 When one pole only was in the water and the other in the air 

 over it, still the decomposition, and therefore the conduction, 

 was electrolytic ; for one element appeared at the pole in the 

 water, and the other in the air or gas over the water at the cor- 

 responding pole. Buff concludes that electrolytes have no con- 

 duction proper. Many other philosophers have supported, with 

 more or less conviction, the same view, and believe that electro- 

 lytic conduction extends to, and includes cases which formerly 

 were supposed to depend upon conduction proper. Sorct ad- 

 vances certain experimental results f, but reserves his opinion 

 from being absolute. Von Breda and Logeman adopt the more 



* MS. letter. t Annates de Chimie, xlii. 257- 



