Finally, my note to (79.) says that the Lycee, No. 36. "mistakes the erroneous results of MM. Fresnel and Ampere for true ones," &c. &c. In calling M. Ampere's results erroneous, I spoke of the results described in, and referred to by the Lycee itself; but _now_ that the expression of the direction of the induced current is to be separated, the term _erroneous_ ought no longer to be attached to them. April 29, 1833. M.F.] FOURTH SERIES. S 9. _On a new Law of Electric Conduction._ S 10. _On Conducting Power generally._ Received April 24,--Read May 23, 1833. S 9. _On a new Law of Electric Conduction._[A] [A] In reference to this law see further considerations at 910. 1358. 1705.--_Dec. 1838._ 380. It was during the progress of investigations relating to electro-chemical decomposition, which I still have to submit to the Royal Society, that I encountered effects due to a very _general law_ of electric conduction not hitherto recognised; and though they prevented me from obtaining the condition I sought for, they afforded abundant compensation for the momentary disappointment, by the new and important interest which they gave to an extensive part of electrical science. 381. I was working with ice, and the solids resulting from the freezing of solutions, arranged either as barriers across a substance to be decomposed, or as the actual poles of a voltaic battery, that I might trace and catch certain elements in their transit, when I was suddenly stopped in my progress by finding that ice was in such circumstances a non-conductor of electricity; and that as soon as a thin film of it was interposed, in the circuit of a very powerful voltaic battery, the transmission of electricity was prevented, and all decomposition ceased. 382. At first the experiments were made with common ice, during the cold freezing weather of the latter end of January 1833; but the results were fallacious, from the imperfection of the arrangements, and the following more unexceptionable form of experiment was adopted. 383. Tin vessels were formed, five inches deep, one inch and a quarter wide in one direction, of different widths from three eighths to five eighths of an inch in the other, and open at one extremity. Into these were fixed by corks, plates of platina, so that the latter should not touch the tin cases; and copper wires having previously been soldered to the plate, these were easily connected, when required, with a voltaic pile. Then distilled water, previously boiled for three hours, was poured into the vessels, and frozen by a mixture of salt and snow, so that pure transparent solid ice intervened between the platina and tin; and finally these metals were connected with the opposite extremities of the voltaic apparatus, a galvanometer being at the same time included in the circuit.