That, broadly stated, was the information which Helmholtz first conveyed to me in terms which I understood clearly; and for this service I have always been profoundly grateful to him. He showed me that the Faraday-Maxwell electromagnetic theory was incomparably simpler than I thought it to be, and also much more beautiful. I do not believe that in 1881 there was another physicist in continental Europe who could have given me that information, and perhaps not even in 1886, when I first read that wonderful address. My friend Niven in Cambridge, editor of the second edition of Maxwell’s great mathematical treatise, never volunteered to tell me how Maxwell answered the question: “What is Light?” Neither did Tyndall. I do not know whether Rayleigh or Stokes or anybody else in Cambridge when I was there could have done it as well as Helmholtz did. I shall describe later an historical event which indicates that they probably could not. Toward the end of that semester I felt certain that I understood Helmholtz’s interpretation of Faraday, and of Maxwell’s answer to the question: “What is Light?” I then managed to have another discussion with Professor Koenig. He listened most attentively to my description of the Faraday-Maxwell electromagnetic theory as I had gathered it from Helmholtz; and it was, as far as I can recall it now, very similar to the description given above. This was my first lecture at the University of Berlin, delivered to a very intelligent audience of one person, dear little Doctor Koenig. It would have been a signal success if I had not closed it with a tactless remark, to the effect that Helmholtz, in his Faraday address, rejected every one of the four German electrical theories, and declared himself in favor of Faraday and Maxwell. Helmholtz intimated, and unfortunately I did not hesitate to say so to Doctor Koenig, that physicists of continental Europe had not accepted the English theory because it was above their heads. Finally I said that all this explained most satisfactorily why Kirchhoff paid so little attention to Faraday and Maxwell. Koenig looked at his watch, and, as if suddenly remembering an important engagement, he turned on his heels and left without his customary bow and greeting. His national pride was evidently wounded. I regretted it deeply. I did my best to make up with him and succeeded finally, by admitting unreservedly that, after all, the Faraday-Maxwell electromagnetic theory rested upon several bold assumptions which had not yet been verified by experiment. The German electrical theories also rested upon unverified assumptions, but I said nothing about that for fear of endangering the re-established _entente cordiale_ between Doctor Koenig and myself.