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

In the autumn of 1927 (Wood says) I made an astonishing discovery. During the spring before, I had observed that the fluorescence of mercury vapor excited by the blue light of the mercury arc was quite strongly polarized, a condition that is recognized by the appearance of dark bands crossing the luminous patch when viewed with a Nicol prism and quartz wedge. Returning to my laboratory in the fall, I started work again, but now was unable to repeat my observations. There was no trace of polarization whatever. The setup of apparatus, lamp, mercury tube, optical parts, had not been altered. I tried to think of some slight change that I had made and forgotten, but could think of nothing except that I had turned the table around so as to get one end away from the sink. What effect could that have? Obviously none; but how about the earth’s magnetic field? Fantastic idea! But I turned the table with all its load of apparatus back to its former position and lighted the mercury lamp. I looked through the polarization detector, and there were the black bands crossing the spot of green fluorescent light of the mercury vapor. Picking up a three-cornered file that was lying on the table I held it near the tube, and the dark fringes vanished. The file had been magnetized by some previous contact with a magnet, as were most of the files in my laboratory. Never before had so weak a magnetic field as that of the earth been found to affect any optical phenomenon, and work was immediately started in collaboration with Alexander Ellett, one of my best students. Our first problem, of course, was to neutralize the earth’s magnetic field in the vicinity of the apparatus, which was done by a pair of wire coils carrying a carefully adjusted current. The investigation occupied us for two years, for we found still more interesting and complicated effects with the vapor of sodium, in which case we were dealing with the simpler phenomenon of resonance radiation, instead of with fluorescence. These results opened up a wide field of new research on the effects of magnetism on light sources, and many papers appeared by other investigators.

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In the autumn of 1927 a gathering of the world’s most prominent physicists met at Como, birthplace of Volta, for the celebration of the one hundredth anniversary of his death. Wood went abroad with his wife and Elizabeth.

There were solemn exercises at the tomb of Volta, receptions, boat excursions by day and night, garden parties, and motor trips to Pavia and other places.

On the last night (says Wood), there was a display of fireworks on the lake, which I have never seen equaled anywhere. It ended with a 200-yard barrage of phosphorus and magnesium bombs which exploded with terrific reports and blinding flashes of light, which were particularly effective when the great smoke clouds enveloped the flashes in a heavy veil. It is the only pyrotechnic piece I have ever seen that made cold chills run up and down my spine. It was a dramatization of war, and was terrific.

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At the end of the ceremonies, the delegates went down to Rome, where other entertainment was provided, ending with a reception and afternoon tea party given by Mussolini at his Villa Corsini. They all had to be recognized by at least three members of the reception committee before being admitted.

Wood’s second trip abroad with Alfred Loomis was made in 1928. They called first on Sir Oliver Lodge, who presented each of them with an autographed copy of his latest book, Evidence of Immortality. They next visited Sir Charles V. Boys, whom Loomis invited to go back with them in July and spend the summer in Tuxedo. Boys said, “Oh, I haven’t been to America for twenty years, and I should like to see it now with all the changes, but I’m pretty feeble, and I tremble at the thought of such a journey. It is frightening!” His son, however, urged him to accept, and Alfred said, “All you have to do is to be in Plymouth on July 4, and I’ll arrange everything else”.

One of the things Loomis hoped to obtain in England was an astronomical “Shortt clock”, a new instrument for improving accuracy in measurement of time. It had a “free pendulum” swinging in a vacuum in an enormous glass cylinder — and was so expensive that only five of the big, endowed observatories yet possessed one. Says Wood: