A JUBILANT EPISTLE.
§ III. The new electrical condition which intervenes by induction between the beginning and end of the inducing current gives rise to some very curious results. It explains why chemical action or other results of electricity have never been as yet obtained in trials with the magnet. In fact, the currents have no sensible duration. I believe it will explain perfectly the transference of elements between the poles of the pile in decomposition but this part of the subject I have reserved until the present experiments are completed and it is so analogous, in some of its effects to those of Ritter’s secondary piles, De la Rive and Van Beck’s peculiar properties of the poles of a voltaic pile, that I should not wonder if they all proved ultimately to depend on this state. The condition of matter I have dignified by the term Electrotonic, The Electrotonic State. What do you think of that? Am I not a bold man, ignorant as I am, to coin words but I have consulted the scholars,[26] and now for § IV. The new state has enabled me to make out and explain all Arago’s phenomena of the rotating magnet or copper plate, I believe, perfectly; but as great names are concerned Arago, Babbage, Herschel, &c., and as I have to differ from them, I have spoken with that modesty which you so well know you and I and John Frost[27] have in common, and for which the world so justly commends us. I am even half afraid to tell you what it is. You will think I am hoaxing you, or else in your compassion you may conclude I am deceiving myself. However, you need do neither, but had better laugh, as I did most heartily when I found that it was neither attraction nor repulsion, but just one of my old rotations in a new form. I cannot explain to you all the actions, which are very curious; but in consequence of the electrotonic state being assumed and lost as the parts of the plate whirl under the pole, and in consequence of magneto-electric induction, currents of electricity are formed in the direction of the radii; continuing, for simple reasons, as long as the motion continues, but ceasing when that ceases. Hence the wonder is explained that the metal has powers on the magnet when moving, but not when at rest. Hence is also explained the effect which Arago observed, and which made him contradict Babbage and Herschel, and say the power was repulsive; but, as a whole, it is really tangential. It is quite comfortable to me to find that experiment need not quail before mathematics, but is quite competent to rival it in discovery; and I am amused to find that what the high mathematicians have announced as the essential condition to the rotation—namely, that time is required—has so little foundation, that if the time could by possibility be anticipated instead of being required—i.e. if the currents could be formed before the magnet came over the place instead of after—the effect would equally ensue. Adieu, dear Phillips.
Excuse this egotistical letter from yours very faithfully,
M. Faraday.
The second section shows that Faraday had discovered the cause of all the previous failures to evoke electric currents in wires by means of a magnet: it required relative motion. What the magnet at rest fails to do, the magnet in motion accomplishes. This crucial point is admirably commemorated in the following impromptu given by Mr. Herbert Mayo to Sir Charles Wheatstone:—
Around the magnet Faraday
Was sure that Volta’s lightnings play:
But how to draw them from the wire?
He took a lesson from the heart:
’Tis when we meet, ’tis when we part,