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

Chapter Fifteen. Wood Covers the World

Wood’ s fiftieth birthday had occurred in the year of the armistice. The years which followed saw him entering an era of speeded-up activities, scientific and social, which would have left most younger men out of breath and panting.

He detests the word “social” and “society”, but this petulance doesn’t alter the fact that he and the whole family have always loved parties and gaiety. By 1918 they had become international cosmopolites, shuttling in the summertime from great country houses in England to Paris and Brittany, to St.-Jean-de-Luz, to St.-Moritz in winter, playing with the most dazzling playboys and playgirls of the period as well as consorting with fellow-celebrities in Wood’s own world of science.

A complete record of the Wood family’s ocean trips, parties, visits to Aix-les-Bains, Baden-Baden, Biarritz, Venice, and the Lido during the twenties and thirties would give the false impression that Wood himself was an international playboy. Yet it was during these same years that he conducted many of his most important researches and made some of his greatest contributions to science. The man is definitely a hyperkinetic, yet never burns out his fuses.

Wood was no sooner out of the army and back in Baltimore than he took up his work with sodium where he had left off before the war. In 1919 he announced the discovery that thin films of metallic sodium and potassium, condensed on the inner surface of fused quartz bulbs at liquid-air temperature, while so opaque to light that the sun was invisible through them, were transparent to the entire range of the ultraviolet as far as wave length 2,000. The discovery was of considerable importance in connection with the new theory of the optical properties of metals. At the same time Wood became interested in the mystery of the hydrogen spectrum — the fact that while all terrestrial sources of luminous hydrogen gave spectra with only eight of the so-called Balmer series of lines, the spectra of the sun’s chromosphere and many stars showed thirty-three members of the series. The result of his investigation is such a good example of how research in pure science can have immediate practical importance that I let him tell it himself.

Bohr, the great Danish physicist, whose explanation of the Balmer series of hydrogen had created a sensation at the Birmingham meeting of the British Association, had told me that he believed that the absence of the higher members of the series in vacuum tubes might result from the circumstance that the atoms were too close together to allow room for the larger electronic orbits, which, on his new theory of radiation, were responsible for the shorter ultraviolet radiations, whereas in hydrogen stars there might be room for these orbits owing to the lower pressure of the gas. This didn’t seem a promising line of attacking the problem in the laboratory, since the luminosity in a vacuum tube decreases enormously as the pressure is lowered, but I decided to give it a trial.

To make up for the loss of light, which was sure to result from the lowering of pressure, I made a tube over three feet in length. The two ends, terminated by large bulbs for the electrodes, were bent at a right angle, so that light from the entire tube could escape from a small, thin-walled bulb blown at the bend. The tube was excited by a powerful high-potential transformer, but when pumped to very low pressure showed only two or three of the Balmer lines and a host of the hundreds of lines that we now know are due to molecular hydrogen. This was clearly the wrong idea, but at higher pressures, the lines that I wanted came out much stronger, and the other lines grew fainter, and conditions seemed to be improving from day to day. Moist hydrogen was flowing into the tube all the time through a long tube the size of a horsehair, and the pump was working at the other end continuously. On the third day the central part of the tube was shining with a fiery purple color of almost unsupportable brilliancy, the spectroscope showed that only the Balmer series of lines were being emitted, and I eventually succeeded in photographing twenty- two members of the series, more than doubling the number previously found in the laboratory. Further study showed that the improvement resulted from the circumstance that only hydrogen atoms were present in the tube. These emit the Balmer lines, while the molecules, which consist of two atoms bound together, give a very complicated spectrum made up of thousands of lines. These, and the continuous background which accompanies them, were the cause of the obliteration of the Balmer lines of shorter wave length in all previous work. As the work proceeded I found that the success of the operation resulted from the fact that the atomic hydrogen formed by the powerful discharge could combine into the molecular gas only by coming in contact with the walls of the tube or the aluminum electrodes. The central part of the long tube was so far removed from the electrodes that they were inoperative in this region, and the water vapor, which entered along with the hydrogen, formed a film on the walls, which “poisoned” them, as Langmuir pointed out, so that they were no longer operative in recombining the atoms into molecules.

The most remarkable observation of all was made when a short loop of fine tungsten wire had’been mounted in a short side tube, for another experiment. It was to be heated white hot by a storage battery to see whether shooting free electrons into the discharge would have any effect. To my amazement the wire remained white hot after I had opened the switch to the storage battery, though it was not in the line of the discharge, but in a little side tube. Aston, the English physicist, happened to come into my room at the moment, and opened his eyes when he saw what was happening. He suggested that a parasitic discharge might be flowing from the main current to the battery, which was still connected by one wire with the tungsten filament, so I disconnected both wires where they were attached to the tungsten; but the filament continued to shine like an automobile lamp. It turned out that the tungsten was causing the recombination of the hydrogen atoms into molecules, and the heat of recombination was sufficient to maintain the wire at a white heat. The results of these experiments were published in two papers in the Proceedings of the Royal Society.

Shortly afterwards I demonstrated the effect before the research staff of the General Electric Company at Schenectady, making the vacuum tube on the spot. As I showed it here the tungsten filament was mounted in the side tube leading to the pump. The pressure was only about 1/700 of that of the atmospheric, and the atomic gas was practically at room temperature, yet the wire was kept at incandescence by a cold stream of atomic hydrogen. Dr. Langmuir was much intrigued and began to speculate on what could be accomplished with a stream of the gas at atmospheric pressure. His speculation led to an important invention, for in less than six months he took out a patent for an atomic hydrogen welding torch, which proved of immense value, since all sorts of metals could be welded in a hydrogen atmosphere without showing flaws or blowholes.

It was as a consequence of Wood’s scientific zest and social strenuousness that fate brought him, about this time, the facilities of a great private laboratory backed by a great private fortune. He had met Alfred Loomis during the war at the Aberdeen Proving Grounds, and later they became neighbors on Long Island. Loomis was a multimillionaire New York banker whose lifelong hobby had been physics and chemistry. Loomis was an amateur in the original French sense of the word, for which there is no English equivalent. During the war, he had invented the “Loomis Chronograph” for measuring the velocity of shells. Their friendship, resulting in the equipment of a princely private laboratory at Tuxedo Park, was a grand thing for them both. To say that the conjunction was like that of Leonardo da Vinci and Lorenzo the Magnificent would be a wrong comparison, since Wood’s nature is such that not even God Almighty could ever be a patron to him.

A happy collaboration began, which came to its full flower in 1924. Here is Wood’s story of what happened.

Loomis was visiting his aunts at East Hampton and called on me one afternoon, while I was at work with something or other in the barn laboratory. We had a long talk and swapped stories of what we had seen or heard of “science in warfare”. Then we got onto the subject of postwar research, and after that he was in the habit of dropping in for a talk almost every afternoon, evidently finding the atmosphere of the old barn more interesting if less refreshing than that of the beach and the country club.

One day he suggested that if I contemplated any research we might do together which required more money than the budget of the Physics Department could supply, he would like to underwrite it. I told him about Langevin’s experiments with supersonics during the war and the killing of fish at the Toulon Arsenal. It offered a wide field for research in physics, chemistry, and biology, as Langevin had studied only the high- frequency waves as a means of submarine detection. Loomis was enthusiastic, and we made a trip to the research laboratory of General Electric to discuss it with Whitney and Hull.

The resulting apparatus was built at Schenectady and installed at first in a large room in Loomis’s garage at Tuxedo Park, New York, where we worked together, killing fish and mice, and trying to find out why and how they were killed, that is whether the waves destroyed tissue or acted on the nerves or what.

The generator was an imposing affair. There were two huge Pliotron tubes of two kilowatts output, a huge bank of oil condensers, and a variable condenser with intersecting wings of the type familiar to every amateur radio operator, but about six feet high and two feet in diameter. Then there were the induction coil for stepping up the voltage and the circular quartz plate with its electrodes in an oil bath in a shallow glass dish. With this we generated an oscillatory electric potential of 50,000 volts at a frequency of from 200,000 to 500,000 alternations per second. This oscillating voltage applied to the electrodes on the quartz plate caused it to expand and contract at the same frequency, and generate supersonic waves in the oil, the pressure of which against the surface of the oil raised the thick liquid in a mound nearly two inches in height, surmounted by a fountain of oil drops some of which were projected to a height of a foot or more. We could conduct the sonic vibrations out of the oil into glass vessels and rods of various shapes by dipping them in the oil over the vibrating plate, and found they could be transmitted along a glass thread the size of a thick horsehair to a distance of a yard or more. If the end of the thread was held lightly between the thumb and finger, no sensation was produced, but if it was pinched it felt almost red hot, and in a second the skin was burnt white in the form of a groove. A thin glass rod when carrying the waves and pressed firmly against a pine stick caused it to emit smoke and sparks, the rod burning its way through the wood, leaving a hole with blackened edges. If a glass plate was substituted for the pine stick, the vibrating rod drilled its way through the plate, throwing out the displaced material in the form of a fine powder or minute fused globules of glass. If the waves were passed across the boundary separating two such liquids as oil and water or mercury and water, more or less stable emulsions were formed. Blood corpuscles were exploded, the red coloring matter escaping and staining the saline solution with which it had been mixed, making a clear transparent red like an aniline dye. These and a host of other new and interesting effects were discovered in the first two years of our experiments.

As the scope of the work expanded we were pressed for room in the garage and Mr. Loomis purchased the Spencer Trask house, a huge stone mansion with a tower, like an English country house, perched on the summit of one of the foothills of the Ramapo Mountains in Tuxedo Park. This he transformed into a private laboratory de luxe, with rooms for guests or collaborators, a complete machine shop with mechanic and a dozen or more research rooms large and small. I moved my forty-foot spectrograph from East Hampton and installed it in the basement of the laboratory so that I could continue my spectroscopic work in a better environment. Mr. Loomis had a new tube made for the instrument, since there was no point in digging up the underground sewer pipes which had served formerly. He packed the tube in boiler felt with an arrangement for keeping the entire tube at a constant temperature, had a new and better camera made, installed motors, revolution counters, etc., for rotating the grating, which was housed in a small closet built around the brick pier on which it was mounted, and arranged other substitutions and gadgets, until I told him there was nothing left of my celebrated spectrograph but the forty feet. It had experienced a “reincarnation”, and required no pussycat as housemaid.

Loomis, who was anxious to meet some of the celebrated European physicists and visit their laboratories, asked Wood to go abroad with him. They made two trips together, one in the summer of 1926, the other in 1928. Going over on the Ile de France early in July, 1926, they were met at Plymouth by a Daimler in which they were driven to Hereford for a visit with Wood’s friend Thomas R. Merton, professor of physics at Oxford and now treasurer of the Royal Society. His estate bordered on the River Wye, and their arrival coincided with the salmon-fishing season. Merton had a fine private laboratory behind the house and some interesting experiments to show, but for once Loomis was excited over something other than physics. He waded in the Wye and landed a fifteen- pound salmon.

In Paris they had a fine time visiting laboratories, among them that of Dr. Jean Saidman, who was interested in the applications of ultraviolet light in the practice of medicine. He had much to say about Lumière Wood, which was the name the French had given it during the war. Wood says his own name is unfortunate since in translation it frequently becomes confused with the noun. An American consul in Paris once sent a report to the State Department that the French were finding important industrial applications for the light of a mercury arc passed through a “wooden screen”, his translation of “écran de Wood”. Dr. Saidman had all sorts of electrical apparatus, including an X-ray machine with a fluoroscope. Loomis had never witnessed the action of the human stomach, and the doctor politely offered to use Wood as a guinea pig. He was given a dose of barium carbonate, after which Loomis’s request was granted. Wood insisted on a mirror so that he could witness the process too.

They finally sailed for home on the Olympic.

Wood’s sensational and exciting circus methods of presenting scientific data had a queer and beautiful repercussion in 1926. The Franklin Institute in Philadelphia decided to sponsor a Christmas-week series of scientific lectures for children similar to those which Faraday had organized ninety years ago at the Royal Institution in London. Dr. Wood was invited to inaugurate the lectures with a talk on “Recreations with Radiations”.

He selected from all of the optical experiments with which he was acquainted a large assortment of the most spectacular, and in particular those which could be shown by projection, for many actual experiments can be shown in operation on a large white screen with an even greater brilliancy than that of motion pictures. From these he selected the ones which young people could understand, and arranged them in such order that a logical, continued story could be built up, beginning with the simpler ideas and going on gradually to the discussion of more difficult material. In particular, he worked out a method of projecting on the screen a much longer and more brilliant spectrum than had ever been shown before, so far as he knows. It was about a foot in width and ten feet long, the rainbow colors having a high degree of purity. With this as a background he showed numerous experiments on the absorption of light by various vapors, fluids, and solids, the bright-line emission spectra of metallic arcs, and related phenomena. A host of experiments with the brilliant-colored patterns produced by polarized light and some of his early experiments with sodium were also on the program, with the demonstration of its taking fire when thrown on water, and the story of the people who were scared to death by the “man who spit fire in a puddle”.

In the audience was nine-year-old Kern Dodge, grandson of Mrs. James Mapes Dodge and great-grandson of Mary Mapes Dodge, founder and long-time editor of St. Nicholas. The lecture had so filled this little boy with passionate joy and excitement that he went home in a sort of holy glow which set fire to his grandmother — whereupon she wrote out a check for $10,000 to endow the Christmas lectures for children and make them permanent.

Meanwhile, Wood’s scientific work was opening up new fields for study.

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.

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.

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:

I took Loomis to Mr. Hoke-Jones, who made the clocks. His workshop was reached by climbing a dusty staircase, and there was little or no machinery in sight, but one of the wonderful clocks was standing in the corner, almost completed, which made the total production to date six. Mr. Loomis asked casually what the price of the clock was, and on being told that it was two hundred and forty pounds (about $1,200), said casually, “That’s very nice. I’ll take three”. Mr. Jones leaned forward, as if he had not heard, and said, “I beg your pardon?” “I am ordering three”, replied Mr. Loomis. “When can you have them finished? I’ll write you a check in payment for the first clock now”.

Mr. Jones, who up to then had the expression of one who thinks he is conversing with a maniac, became apologetic. “Oh, no”, he said, “I couldn’t think of having you do that, sir. Later on, when we make the delivery, will be quite time enough”. But Loomis handed him the check nevertheless.

During the ensuing weeks they motored about England, visited the continent, and returned, showed motion pictures of the supersonic experiments before the Royal Society, went to the Derby, lunched and dined with celebrities — and then took a flying trip to Copenhagen, where they saw Niels Bohr, and then went on to Germany.

Again, at Berlin University, they showed motion pictures of their supersonic experiments, met Pringsheim, von Laue, Planck, Nernst, and most of the other famous scientists then alive in Germany. They visited the Zeiss works at Jena and the University of Gottingen, where they were invited to see a student duel. Wood was all for seeing it, but dueling was, of course, against the law, and Loomis was unwilling.

We hadn’t heard from Boys meanwhile (says Wood), and it was time to be getting aboard the Paris. Loomis had sent Boys his steamer ticket, but we had no means of knowing whether or not his courage would hold out. As the liner slowed down at Plymouth to take on the English passengers, we looked anxiously down on the little tender, and there he was waving his hand joyfully and all ready to scramble up the gangplank, looking as relieved at finding us really on the steamer as were we at seeing him on the tender.

We had the best of everything on the boat, and the Chief Steward had a special surprise for us every night at dinner, marvels of French cooking. On the last day he announced at lunch that he had a grand surprise, something very unusual, a great luxury! “Epatant! Only wait and see”. Sure enough, after the soup and fish a wagon was solemnly rolled up to our table, bearing a great silver dish covered with an oval silver dome. The Chief Steward was in attendance. He rubbed his hands together and smiled at us, and then lifted the cover, displaying in all its stark nakedness a huge shapeless mass of shivering, steaming corned beef, garnished with cabbage and cauliflower and whatever else goes with this, my pet abomination, a New England boiled dinner.

Back in America, they learned that Professor James Franck, Nobel prize winner, was coming over in January to give lectures at various universities. Wood suggested to Loomis that he hold a congress of physicists in his Tuxedo Park laboratory in Franck’s honor. Franck accepted and the meeting was held in the library, a room of cathedral-like proportions, with stained- glass windows. Franck gave his first lecture in America there. Wood, Loomis, and others made subsequent addresses. The visiting American physicists were conducted through the laboratory and shown the supersonic and other experiments. The congress in this palace of science proved such a success that it was repeated the following year.