Doctor Wood. Modern Wizard of the Laboratory: The Story of an American Small Boy Who Became the Most Daring and Original Experimental Physicist of Our Day-but Never Grew Up

He had been puzzling over what form the light wave must assume in some of the complicated processes of reflection, as, for example, in a hollow spherical mirror. It occurred to him that this question might be solved by making use of the analogy between sound and light. A German physicist named Toepler had devised an instrument by which it was possible to photograph the spherical sound wave given off by the “snap” of an electric spark. This wave is, in fact, a spherical shell of highly compressed air, which expands with velocity of more than a thousand feet per second. To catch it before it has passed out of the field of the camera, it must be illuminated by the light of a second spark which occurs at about one ten- thousandth of a second later. With Toepler’s instrument, he made a long series of photographs of sound waves undergoing reflection and refraction, as well as diffraction and dispersion. One of the photographs showed the reflection of a sound wave from a little flight of steps made of glass and placed beneath the spark. The echo from the flight of steps consisted of a train of waves and constituted a musical note of high pitch. This phenomenon, the conversion of an explosive sound into a musical note, can be verified by clapping the hands together in front of a flight of steps, if one is in the open air where no echoes from the walls or ceiling interfere with the observation of the musical note which is echoed back from the steps.

The reflection of these waves from curved surfaces was extremely complicated. He first worked out a geometrical method of constructing their forms from theory, as they went through their contortions. These evolutions he drew on paper in black ink, by the hundreds, and then photographed them one at a time in succession on motion-picture film, which had only just been put on the market. Next he obtained a machine for projection, and found that the method gave admirable results. The black line representing the sound wave moved along, twisting and folding back upon itself in curious ways, and gave a striking picture of what was actually also happening to light waves in the case of reflection of light under similar conditions. Practically all of the optical phenomena of reflection and refraction of light were reproduced by sound waves and could now be studied in a new way.

The results were communicated to scientific journals here and abroad. Also the daily newspapers, caring nothing about the analogy with light waves — which was the only thing Wood did care about — were excited by the novelty of “seeing” sound waves, and reproduced page after page of the photographed drawings.

In January, 1900, Wood received an invitation from the Royal Society of Arts asking him to come to London and deliver a lecture on his color photography at the February meeting. Then came a letter from the physicist, Sir Charles Vernon Boys, inviting him to present before the Royal Society his animated photographs of sound waves. There are many Royal Societies, Royal Astronomical, Royal Photographic, Royal Microscopical, Royal Society of Arts, and Royal What-Have-You, but there is only one Royal Society tout court — founded in 1660 and unquestionably the most important scientific body in the world. Professor Snow was greatly excited and took the matter up with President Adams, who took it up with the Regents of the University, and Wood was given a two months’ leave of absence.

Boys met him on his arrival in London, put him up at the Savile Club and the Athenaeum, and secured suitable “lodgings” for him just around the corner from the former. His lecture before the Society of Arts was on St. Valentine’s day, with Sir William Abney in the chair. But the great occasion was still to come…

The young American professor’s appearance before the Royal Society was scheduled for the following afternoon. Boys had finally located and set up a motion picture projecting machine, of which there were then only two in London.

When they entered the sacred portals, the Fellows of the Society were having tea in the noble assembly room from which they all presently proceeded to the auditorium. Lord Lister, the venerable father of antiseptic surgery, presided from a thronelike chair behind an elevated desk. The great gold mace of Cromwell’s time was brought in on a red velvet cushion and laid solemnly on the desk in front of the president. Cromwell had treated it with less formality, and his celebrated order, “Remove that bauble!” has echoed down the ages.