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.

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1646.  There is a very remarkable phenomenon or effect of the electrolytic discharge, first pointed out, I believe, by Mr. Porrett, of the accumulation of fluid under decomposing action in the current on one side of an interposed diaphragm[A].  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 condition 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[B], 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[C] the contrary is the case, and that, the effect is not directly due to the electric current.

  [A] Annals of Philosophy, 1816. viii. p. 75.

  [B] Annales de Chimie, 1835. xxviii. p. 196.

  [C] Annales de Chimie, 1832, xlix. p. 423.

1647.  Becquerel, in his Traite de l’Electricite, has brought together the considerations which arise for and against the opinion, that the effect generally is an electric effect[A].  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 convection (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 surfaces 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[B], which will probably bear importantly on this point.

  [A] Vol. iv. p. 192, 197.

  [B] Traite de l’Electricite, i. p. 285.

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1648. As long as the terms current and electro-dynamic are used to express those relations of the electric forces in which progression of either fluids or effects are supposed to occur (283.), so long will the idea of velocity be associated with them; and this will, perhaps, be more especially the case if the hypothesis of a fluid or fluids be adopted.