xxix 



pleted ; and it is so analogous, in some of its effects, to those of v Hitter'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 ulti- 

 mately 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, and now for IV. 



" 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 mo- 

 desty which you so well know you and I and John Frost * 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 rota- 

 tions 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 direc- 

 tion of the radii, — continuing, for simple reasons, as long as the motion con- 

 tinues, 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 re- 

 pulsive ; 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 amazed to find 

 that what the high mathematicians have announced as the essential con- 

 dition to the rotation, namely, that time is required, has so little foun- 

 dation, 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." 



Mt. 40 (1832). 



The second series of Experimental Researches in Electricity was this year 

 the Bakerian lecture on Terrestrial Magneto- electric Induction, and on the 

 Force and Direction of Magneto-electric Induction generally. 



His Friday discourses were, (1) on Dr. Johnson's Researches on the Re- 

 productive Power of Planarise ; (2) recent experimental Investigation of 

 Volta-electric and Magneto-electric Induction ; (3) Magneto-electric In- 



* A pushing acquaintance, who, without claim of any kind, got himself presented at 

 Court. 



