If the wire be made to revolve round the pole, the motions are according to those mentioned. In the apparatus I used there were but two plates, and the directions of the motions were of course[19] the reverse of those with a battery of several pairs of plates, and which are given above. Now I have been able, experimentally, to trace this motion into its various forms as exhibited by Ampère’s, Nelice’s, &c., and in all cases to show that the attractions and repulsions are only appearances due to this circulation of the pole, to show that dissimilar poles repel as well as attract, and that similar poles attract as well as repel, and to make, I think, the analogy between the helix and common bar magnet far stronger than before. But yet I am by no means decided that there are currents of electricity in the common magnet. I have no doubt that electricity puts the circles of the helix into the same state as those circles are in, that may be conceived in the bar magnet, but I am not certain that this state is directly dependant on the electricity, or that it cannot be produced by other agencies; and therefore, until the presence of electrical currents be proved in the magnet by other than magnetical effects, I shall remain in doubt about Ampère’s theory. * * * * * Wishing you all health and happiness, and waiting for news from you, I am, my dear Sir, your very obliged and grateful M. FARADAY. The reference at the beginning of this letter to the chlorides of carbon has to do with his discovery communicated to the Royal Society. Later in the year, a joint paper on another compound of carbon and chlorine, by himself and his friend Richard Phillips, was sent in. Both were printed together in the _Philosophical Transactions_ of 1821. [Sidenote: LEAVES FROM THE NOTE-BOOK.] The following is an extract from Faraday’s laboratory book relating to the discovery. The account is incomplete, a leaf having been torn out:-- 1821, Sept. 3. The effort of the wire is always to pass off at a right angle from the pole, indeed to go in a circle round it, so when either pole was brought up to the wire perpendicular to it and to the radius of the circle it described, there was neither attraction nor repulsion, but the moment the pole varied in the slightest manner either in or out, the wire moved one way or the other. The poles of the magnet act on the bent wire in all positions and not in the direction _only_ of any axis of the magnet, so that the current can hardly be cylindrical or arranged round the axis of a cylinder?