CHARACTER OF THE CURRENT — PORRETT'S PHENOMENA. 163 



mode of expression) had existed : or, if the ball be negatively electrified, and then 

 moved, effects as if a current in a direction contrary to that of the motion had been 

 formed, will be produced. 



1645. I am saying of a single particle or of two what I have before said, in effect, 

 of many (1633.). If the former account of currents be true, then that just stated 

 must be a necessary result. And, though the statement may seem startling at 

 first, it is to be considered that, according to my theory of induction, the charged 

 conductor or particle is related to the distant conductor in the opposite state, or that 

 which terminates the extent of the induction, by all the intermediate particles (1165. 

 1295.), these becoming polarized exactly as the particles of a solid electrolyte do when 

 interposed between the two electrodes. Hence the conclusion regarding the unity 

 and identity of the current in the case of convection, jointly with the former cases, is 

 not so strange as it might at first appear. 



1646. There is a very remarkable phenomenon or effect of the electrolitic discharge, 

 first pointed out, I believe, by Mr. Porrett, of the accumulation of fluid under de- 

 composing action in the current on one side of an interposed diaphragm *=. It is a 

 mechanical result ; and as the liquid passes from the positive towards the negative 

 electrode in all the known cases, it seems to establish a relation to the polar condi- 

 tion of the dielectric in which the current exists (1164. 1525.). It has not as yet 

 been sufficiently investigated by experiment; for De la Rive says-f-, it requires that 

 the water should be a bad conductor, as, for instance, distilled water, the effect not 

 happening with strong solutions ; whereas, Dutrochet says J the contrary is the case, 

 and that, the effect is not directly due to the electric current. 



1647- Becquerel in his Traits de I'Electricite has brought together the considera- 

 tions which arise for and against the opinion, that the effect generally is an electric 

 effect §. Though I have no decisive fact to quote at present, I cannot refrain from 

 venturing an opinion, that the effect is analogous both to combination and convec- 

 tion (1623.), being a case of carrying due to the relation of the diaphragm and 

 the fluid in contact with it, through which the electric discharge is jointly effected ; 

 and further, that the peculiar relation of positive and negative small and large sur- 

 faces already referred to (1482. 1503. 1525.), may be the direct cause of the fluid and 

 the diaphragm travelling in contrary but determinate directions. A very valuable 

 experiment has been made by M. Becquerel with particles of clay ||, which will pro- 

 bably bear importantly on this point. 



* Annals of Philosophy, 1816. viii. p, 75. f Annales de Chimie, 1835. xxviii. p. 196. 



X Annales de Chimie, 1832. xlix. p. 423. § Vol. iv. p. 197. 192. 



II Traite de I'Electricite, i. p. 285. 



y2 



