“‘May the God of Abraham and the God of Isaac go with the lad!’“
We were sitting one evening under the electric light, steadily burning in the Swan lamps. I asked Sir Joseph how he came to think of devising the lamp which has made his name familiar all over the world. So complicated a topic for the non-expert is the electric light that I am glad not to have to rely upon memory. Sir Joseph kindly undertook to put the matter in writing for me, and here is the narrative in his own words:
“The question you have put to me—although in itself simple—is not easy to answer. The genesis of ideas is often a puzzling matter, and it is so to a considerable extent in the case of my electric lamp. The germ was, I believe, implanted by a lecture on electric lighting that I heard when I was about seventeen. That was in 1845.
“The lecturer was W. E. Staite, one of the first inventors of a mechanically-regulated electric lamp. He illustrated his discourse by brilliant experiments, and was confident in his prediction that electric light would shortly be used for lighthouse illumination. Mr. Staite in his lecture also slightly touched on the production of small electric lights, suitable for house-lighting, and he described and showed how much lighting could be done by electrically heating a wire of Iridium. The experiment he showed to illustrate this point was simply the heating to a white heat a short piece of iridium wire stretched nakedly in the air between two conducting pillars.
“The lecturer was careful to explain that means would have to be provided for regulating the current of electricity, so that the temperature of the wire should not vary, for if too little, the light would be dull, if too much, the wire would melt. I quite clearly remember that while I admired the ingenuity of the mechanism of Staite’s lighthouse lamp, I was not at all satisfied with the too elementary device he proposed for small electric lights.
“As far as it is possible to ‘track suggestion to her inmost cell,’ the train of thought which led, long years after, to the evolution of my electric lamp had its beginning in seeing Mr. Staite’s very simple and very inefficient attempt to produce electric light on a small scale, for I then saw how essential it was that the unit of light must be small and the means of producing it simple for electricity ever to become a widely used means of illumination.
“That is my answer—a very restricted and imperfect answer—to your kindly intended question.
“I have always felt indebted to Mr. Staite for the inspiration he gave me. Unfortunately he did not live to see any great development of electric lighting; he was distinctly an inventor in advance of his time.
“It has always been a pleasure to me to think that Faraday had the joy of seeing ripen some of the first-fruit of his great work in his department of applied science. In his old age he had the gratification of seeing the North Foreland Lighthouse lighted by means of electricity generated in economical manner made possible by his magneto-electrical discoveries. Would that he might have seen their greater results that we see to-day!
“Most sincerely yours,
“Joseph Swan.”