for a moment, still the analogy of air to metal is, electrically considered, so small, that instead of the former replacing the latter (462.), an effect the very reverse might have been expected.  Or if even that were allowed, the experiment with water (495.), at once sets the matter at rest, the decomposing pole being now of a substance which is admitted as competent to transmit the assumed compound of electricity and matter.

508.  With regard to the views of MM.  Riffault and Chompre (485.), the occurrence of decomposition alone in the course of the current is so contrary to the well-known effects obtained in the forms of experiment adopted up to this time, that it must be proved before the hypothesis depending on it need be considered.

509.  The consideration of the various theories of electro-chemical decomposition, whilst it has made me diffident, has also given me confidence to add another to the number; for it is because the one I have to propose appears, after the most attentive consideration, to explain and agree with the immense collection of facts belonging to this branch of science, and to remain uncontradicted by, or unopposed to, any of them, that I have been encouraged to give it.

510.  Electro-chemical decomposition is well known to depend essentially upon the current of electricity.  I have shown that in certain cases (375.) the decomposition is proportionate to the quantity of electricity passing, whatever may be its intensity or its source, and that the same is probably true for all cases (377.), even when the utmost generality is taken on the one hand, and great precision of expression on the other (505.).

511.  In speaking of the current, I find myself obliged to be still more particular than on a former occasion (283.), in consequence of the variety of views taken by philosophers, all agreeing in the effect of the current itself.  Some philosophers, with Franklin, assume but one electric fluid; and such must agree together in the general uniformity and character of the electric current.  Others assume two electric fluids; and here singular differences have arisen.

512.  MM.  Riffault and Chompre, for instance, consider the positive and negative currents each as causing decomposition, and state that the positive current is more powerful than the negative current[A], the nitrate of soda being, under similar circumstances, decomposed by the former, but not by the latter.

  [A] Annales de Chimie, 1807, tom, lxiii. p. 84.

513.  M. Hachette states[A] that “it is not necessary, as has been believed, that the action of the two electricities, positive and negative, should be simultaneous for the decomposition of water.”  The passage implying, if I have caught the meaning aright, that one electricity can be obtained, and can be applied in effecting decompositions, independent of the other.

  [A] Annales de Chimie, 1832, tom. li. p. 73.