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 Eleven. Over the Map

The average university professor is happy if he can take a full year’s sabbatical once in every seven years. But nothing is ever “average” with Wood. He took his first sabbatical in 1910- 11, another in 1913-14, went overseas again in a major’s uniform in 1917, then again soon after the armistice, and has been making long visits to Europe in intervals ever since. His growing international fame, his many invitations to lecture before learned societies abroad, his researches with European colleagues, the funds derived from the Adams endowment for publication of his work by Columbia University, the appreciation of Johns Hopkins, which always gave him half pay during absence, all contributed toward making these triennials not only possible, but reasonable.

Wood began his first so-called sabbatical in the summer of 1910, after devising earlier in the year a new type of diffraction grating which he named the Echelette.[9]

He went first to London, where he delivered the Traill Taylor Memorial Lecture, an annual function of the Royal Photographic Society, and the initial “Thomas Young Oration”, a similar affair just started by the Optical Society. He then joined his family in Paris. Elizabeth, now aged twelve, was placed in school there, and Robert, Junior, aged sixteen, at school in Geneva. Margaret, now a tall young lady of seventeen, accompanied her parents to Berlin.

In Berlin, the Woods found a pension facing the Tiergarten, near the school where Margaret chose to study art. Wood’s amateur talents in this direction had been increased in their transference to the daughter, who later made a name for herself as an outstanding portrait painter.

The family was now joined by their old friends, the Trowbridges. With Trowbridge, Wood attended the celebration of the hundredth anniversary of the founding of the University of Berlin. They went as official delegates from Johns Hopkins and Princeton. The ceremonies were elaborate. Kaiser Wilhelm was there in gorgeous uniform. With him was the pretty crown princess with whom, according to Trowbridge, the irrepressible Wood (delegate from Johns Hopkins!) carried on a mild flirtation during the tedious ceremony.

Soon Wood was deep in research with Professor Rubens, who fifteen years before had encouraged him to change from chemistry to physics. The research with Rubens was on a new method they had developed for isolating and measuring the longest heat waves ever discovered. It was at the time when efforts were being made all over the world to fill the gap in the spectral region between the longest infrared heat waves and the shortest electric or radio waves, for Maxwell’s theory showed that light and electromagnetic waves differed only in length. The method which they discovered was called focal isolation and depended on the odd circumstance that crystalline quartz was exceedingly transparent to a group of waves far longer than any discovered in the infrared, while having at the same time an index of refraction much higher than for visible light, in other words “anomalous dispersion”. They succeeded in isolating heat waves of over 0.1 of a millimeter[10], the longest observed at that time.

Wood announced one day at lunch at the pension in which they were living, “We’ve found and measured the longest heat waves ever observed”.

“How long were they?” asked his daughter Margaret.

“One tenth of a millimeter”, announced Wood triumphantly.

“I don’t call that very long”, commented Margaret in a bored tone.

These invisible rays from the lamp had very curious properties, they found. A quartz plate so heavily smoked that the sun was invisible through it was perfectly transparent to them; and the same was true for a plate covered with a thick opaque layer of finely divided metallic copper, while a plate of hard rubber half a millimeter thick transmitted about 40 per cent.

Plates of rock salt, which are extremely transparent to the greater part of the infrared spectrum previously studied, were absolutely opaque to these rays.

It was a matter of considerable theoretical interest to find out whether an extremely thin plate of salt would transmit anything.

“We need a plate half a millimeter thick, if possible”, said Rubens. “I shall order one from Steinheil [an optician and lens-maker]. He can do it, I think, and we shall have it in two weeks”.

“Why not make it ourselves?” said Wood.

“Can you, then, grind and polish a rock-salt plate?” inquired Rubens in surprise.

“I don’t know”, said Wood. “I think so”.

He took the thinnest salt plate they had and ground it against a sheet of ground glass, slightly moistened with water, until it was about half a millimeter thick. This was all that was required, but the thinner the better, so Wood thought he’d see if he could go further. Attaching the plate to a match stick with sealing wax, he dipped it into a glass of warm water and dried it quickly with absorbent cotton. It was slightly thinner, and the “ground” surface had become polished and transparent. He dipped it in the water and looked at it again (as did the Hatter at the mad tea party). It was still thinner. One more dip proved to be the limit, as the plate showed evidences of going to pieces at one corner.

Rubens breezed into the room, having finished his lecture. “Well”, he said, “and can you make us the salt plate?” “Yes”, said Wood. “It’s finished”.

“And how thick is it?”

“One tenth of a millimeter”, said Wood, who had just finished measuring it.

Early in December the Woods were invited to attend the festivities in Stockholm in connection with the awarding of the Nobel prizes, and Wood was invited to deliver a lecture there on his recent researches in optics.

While carrying on the research with Rubens, he had also been investigating the optical properties of iodine. This had led to a capital discovery which was the small but solid foundation upon which he built later on one of his most important and elaborate series of discoveries, described in numerous papers under the general title of “Resonance Spectra of Iodine”, investigations that occupied him for several succeeding years and eventually, when theory caught up with experiment, were of considerable importance in unraveling the mystery of band spectra. The discovery came about in this way: having been struck, in some of his earlier work, by the similarity of the absorption spectra of sodium and iodine vapors and having prepared some glass bulbs containing iodine vapor for the purpose of studying its fluorescence and passing through one of the rooms in which a quartz mercury arc lamp of great intensity was burning, it occurred to him that possibly the iodine vapor might yield resonance spectra similar to those which he had observed and studied under such difficulties in the case of sodium. He borrowed a small hand spectroscope, set up a large lens, and formed an image of the arc on one of his bulbs. Splendid! A bright cone of fluorescent light inside of the bulb. Pointing the spectroscope at the bulb he observed a resonance spectrum far simpler and more clearly cut than any he had found with sodium, a series of bright lines, spaced with the precision of the graduations on a foot rule, extending from the green line of mercury up through the yellow-orange to the extreme red. This observation was made only a few days before his invitation to Stockholm, so he had a very young “baby” to show at his lecture.

What impressed Wood most on arrival in Stockholm was that it offered no facilities for taking a bath, although there were plenty of places where one could be given a bath. You were placed stark naked on an ironing board and scrubbed with excelsior, like a puppy, by a muscular Swedish woman. The Woods were entertained at dinner by the American Ambassador and his wife, who told Gertrude they had had a bathtub installed in their house, but found that the plumber had put the valves that controlled the hot and cold water flow on the other side of the room from the tub. When they protested that they would have to get out of the tub every time they wanted to change or adjust the temperature, they were told they “could ring for the maid”!

At the huge banquet which followed the handing out of the Nobel prizes, Gertrude was seated at the head table next to Emmanuel Nobel, a nephew of the inventor of dynamite who had founded the prizes. He told her he was just back from St. Petersburg and had brought with him an enormous earthen crock of the finest caviar, a gift from the Czar to the King. “All I could take back as a gift to the Czar”, he said, “would be a box of dynamite — and that, I’m afraid, wouldn’t be very acceptable

When the day came for his lecture, Wood performed a number of what Professor Lorentz, the famous Dutch physicist, had once designated “his beautiful and convincing experiments on the blackboard”, making pictures for his audience of everything he was talking about. It diverted them, he said, and kept them from going to sleep. They must have been well diverted, for the Woods continued to be showered with invitations.

A luncheon was given them by Professor Mittag-Loeffler at his beautiful country home. He was the Chairman of the Nobel Committee, was in Berlin in the autumn, and had extended the invitation to the Woods to come to Stockholm. He was proud of his library, said to be the finest collection of books on mathematics in the world. It was housed in a huge tower, ascended by a great spiral stairway.

Mrs. Wood tells a story about the formal reception which formed a part of the program. The Crown Princess Maud was receiving in a small room which opened off the large hall, and the chamberlain told the Woods they would be taken in soon and presented. Wood was meanwhile introduced to the first lady in waiting, a beautiful and vivacious young Englishwoman, and Mrs. Wood says the chamberlain experienced great difficulty in prying Wood loose from her when the time came for presentation to the Crown Princess.

Wood had an absurd run-in with the German customs. Going to Stockholm he had taken along a suitcase crammed with glass bulbs, lenses, prisms, rubber tubes, and other odds and ends and gadgets for the lecture. When, on the return trip, they reached the German frontier at Malmö and were lined up at the customs barrier, Wood had to open it.

“Ach! Was haben Sie hier?”

Wood explained it had all been made in Germany and was the property of the University of Berlin; that he had taken it to Stockholm for a lecture and was returning it to the University. “That makes no difference”, said the guard. “You have duty to pay”. Wood argued, but to no avail.

The customs officer emptied the case, putting all the glass together, prisms, lenses, and bulbs in one lot, brass gadgets in another lot, rubber tubes in another; and then weighed each lot, noting the weights on a card. He then spent five or ten minutes looking up the rate on glass, brass, and rubber articles, and the quartz mercury lamp, and since he couldn’t properly classify this, about another quarter of an hour slipped by. Finally he added up the column, then added it again to make sure that no mistake had been made, and said triumphantly, “Na — Ja, ja, Sie haben was zu bezahlen! Sie bezahlen zwei Mark fünf und vierzig Pfennig". The English equivalent would be roughly, “You bet your life you have duty to pay! You pay two marks and forty-five pfennigs”. Sixty-two cents for three-quarters of an hour of an official’s misspent time.

Back in Berlin, Wood continued his research, in collaboration with Professor James Franck, subsequently a Nobel prize winner. They had previously worked together on the reduction of intensity of the iodine vapor in fluorescence caused by admixtures of chemically inert gases, and they now made the remarkable discovery that when helium gas was mixed with the iodine vapor, the spectrum of widely separated lines emitted by the vapor when illuminated by the green light of the mercury arc, which Wood had discovered a few weeks before, was transformed into a band spectrum of many hundreds of lines. The theoretical physicists, who occupied themselves with the problems connected with the radiation of atoms and molecules, were unable to find any plausible explanation for any of these effects, and it was not until many years later that they were completely understood, as will appear later. The research with Franck was completed in a couple of weeks, and the paper sent off to the English and German journals of physics.

The Woods next gathered up the family and went to St.- Moritz for Christmas and winter sports. Here Wood got on real skis for the first time, and would have nothing to do with sleds or skates. An ice rink, made by flooding a half-acre rectangle behind the hotel, had no attraction for him. He refused to take lessons, but watched the experts, and bought a book on Skiing without Tears or something of that sort, and at the end of the week could execute in low gear what he optimistically called a Telemark. At the end of the second week, high speed, without sharp turns or sudden stops, did not trouble him, and he had a great thrill, he says, “when, after a climb of over two hours up the mountain behind the village, with spots that called for ‘herring-boning,’ I came down against the wind and sun in one long, wild rush, immunized against terror by excitement, and like Mark Twain in his ‘Lost on the Mountain,’ finally found myself in the back yard of the hotel”.

From St.-Moritz the Woods went to Paris, and Wood started an investigation with an Englishman, Hemsalech, in the laboratory of the Sorbonne, on a new radiant emission from the spark which he had discovered in Baltimore. He also carried out some more accurate measurements of the iodine emission lines than he had been able to make in Berlin.

In the early spring Wood and his wife made a trip to Sicily, and it was here, when the almond blossoms were pinkest, that he made his best and most striking infrared photographs, which were exhibited at the annual exhibition of the Royal Photographic Society a little later and published in the Illustrated London News. They stayed at the Hotel Politi in Syracuse, perched on the brink of the deep quarries of Latomia, in which the hundreds of Athenian prisoners were confined and starved to death after the defeat of Alcibiades by the Syracusians in 414 B.C.. In these quarries Wood made some striking infrared photographs.

I was intrigued greatly (says Wood) by seeing what purported to be the tomb of Archimedes. Reading in boyhood in my father’s old copy of Arnott’s physics about the screw pump for raising water, invented by Ar-kimmy-des (as I always pronounced it), I had constructed one by winding a long piece of lead pipe in a spiral around an old rolling pin from the kitchen closet. History says Archimedes set little value on his mechanical inventions, regarding them as beneath the dignity of pure science, but they were the things that appealed to the popular imagination and have kept his name alive after a lapse of over two thousand years — rather than his contributions to geometry and mathematics.

Wood also is annoyed sometimes when his electrical thaw, his fish-eye views, his color photography process, and other mechanical inventions are stressed in the newspapers as his major achievements.

From Sicily they went to London early in May, 1911, where Wood had been invited to give one of the “Friday evening discourses” at the Royal Institution, founded in 1799 by Count Rumford.

The Friday evening discourses dated back to the time of Sir Humphry Davy and Michael Faraday (whose experiments with electric currents laid the foundations for modern electrical engineering). They were of a semipopular nature, but were full-dress affairs, attended almost exclusively by prominent figures in scientific fields accompanied by their ladies. The lecture hall and its horseshoe-shaped lecture table were the same as they had been when Blaikley did his admirable painting showing Faraday behind the table on which his crude little coils and magnets are displayed, delivering a Friday evening lecture, on December 27, 1855. Wood had often seen the picture, and as a young instructor at Madison had possibly dreamed of one day standing behind this same lecture table, covered with his fluorescent tubes and bulbs, his ultraviolet lamps, electric sparks, and other scientific paraphernalia. Now his dream was coming true.

After the audience is seated (says Wood) there comes a hush in the conversation, and the lecturer and his family, if present, are ushered into the room through a door, previously closed and guarded, behind and a little to one side of the lecture table.

His Grace, the Duke of Northumberland, not being available at the time, Gertrude entered the hall on the arm of the Right Honorable Earl Cathcart, Vice-President, followed by my daughter Margaret, on the arm of diminutive Sir William Crookes, who came nearly up to her shoulder and whose long white mustache, waxed at the ends into two sharp spikes, fascinated her. I brought up the rear. There was a brief introduction and at last I was standing behind the famous lecture table, giving my talk on the recent experiments I had made with invisible light…

The morning after the lecture I was back at the rooms of the Institution, removing my apparatus and putting away in the glass cases such things as I had borrowed. Spying the largest Nicol polarizing prisms that I had ever seen, I asked Sir James Dewar, the director, if I could use them for a study of the polarization of the lines of my newly discovered resonance spectrum of iodine. It was of immense importance to discover if, when the fluorescence spectrum was excited by polarized light of a single color, such as the green line of the mercury arc, any or all of the eighteen lines of the fluorescent spectrum were also polarized. Dewar gave me a nice room to work in and everything that I required. It was going to be a tough job, needing a huge amount of polarized light, large mirrors, and lenses for concentrating it on the bulb containing the iodine vapor, and the big Nicol prisms for polarizing the light. Bulbs had disadvantages, and I adopted a long glass tube of good size with a bulb blown on one end and the other end drawn down like a cow’s horn, bent off to one side and painted black. This served as a dead black background against which the fluorescence could be viewed through the bulb without disturbing reflections from the glass wall. I employed two very powerful quartz mercury arcs, one above and the other to one side of the tube, a huge concave mirror behind each lamp, and two large condensing lenses between the lamps and the tube. The research was completed in a week; all of the lines were found to be strongly polarized and there were excellent photographs showing the dark bands, which indicated polarization, cutting across all of the lines. A twelve-page paper, illustrated with photographs, appeared in the Philosophical Magazine shortly afterwards. This was the fastest work that I had ever done, which was a piece of good luck, for on the day on which I had written finis to it, Dewar strolled in with his hands behind his back under the tails of his frock coat and told me gruffly, as was his habit sometimes, that I’d have to vacate my room, since Marconi was giving the next Friday evening discourse and would need it for setting up and trying out his experiments. “I’m finished”, I said, “and thank you very much”.

It was advertised that at Marconi’s lecture the audience would be able to listen to transatlantic signals coming from Glace Bay, Nova Scotia. This was at a time when some still doubted such a feat was possible.

Kites would be flown from the roof carrying the antenna, and the audience would be able to hear signals by a system of telephones distributed over the auditorium. Days before the lecture, the historic halls of the Institution were invaded by workmen moving in Marconi’s apparatus. They took down the iron balustrade of the marble stairway leading to the second story, which interfered with the hoisting of some of the larger and heavier pieces of electrical equipment to the lecture room. The entrance hall was cluttered with packing boxes and excelsior for three days, and gradually there was assembled, behind the semicircular lecture table on which Faraday had set up his little coils and magnets, such a display of impressive modern electrical appliances as one seldom sees outside a World’s Fair. A great marble switchboard with voltmeters, ammeters, rheostats, inductances, etc., etc.; several mysterious- looking polished mahogany boxes, with shining brass knobs and bars; and many other things in between these. During the afternoon preceding the lecture Marconi’s two young assistants were on the roof of the Institution, raising the tandem of great kites and tuning the receiving instruments.

This interested me enormously, as I had been playing with kites at East Hampton, and I injected myself into the party, asking questions, making suggestions, getting in their way, and making other equally ineffectual efforts to help.

Marconi read his lecture from manuscript, his elbow on the reading desk and his forehead resting on his hand. He appeared to be the least interested person in the auditorium in what he had to say, and there were no experiments. Except that towards the end of his reading he said, “I have installed the apparatus here with which the signals are transmitted and you will hear the sound of the spark discharge in this box when I close the switch”. He opened and closed it several times and we heard “Buz-buz-buz, Buzzzz-buzzzz-buzzzz, buz-buz-buz” (SOS).

About ten minutes before the end of the hour I noticed that his assistants were getting nervous. They were “off stage”, and one of them kept disappearing every few minutes, then reappearing for a hurried whispered conversation. I tiptoed over to find out what was wrong. The transatlantic signals were coming in all right, but the wind was dropping and the kites were coming down.

“Tell Marconi”, I whispered. “Let the audience hear them while they can and then finish the lecture”.

They shook their heads. “Impossible”, one whispered. “They are to come at the end. He would be furious if we interrupted him”.

“Let me do it then”, I said. But they would have none of it.

The lecture went on monotonously, and came to an end with the words: “We shall now listen to the signals coming across the Atlantic”. He turned to his assistants who were standing at the side of the auditorium. They shook their heads, sadly, and one said, “The kites are down”.

Marconi turned to the audience and explained that the failure of the wind had made the demonstration impossible. To me it sounded as if he were slightly pleased to be saved the trouble.

Walking out with Lord Rayleigh after the lecture, I said, “What did you think of it?”

“Well”, he replied, “I feel disposed to think that if you or I had required something for a lecture that would make a buzz- buzz we could have accomplished it with simpler apparatus — and we’d have had the buzz-buzz”.

The Woods now picked up Elizabeth and Robert, Jr., and sailed for home on the maiden trip of the Olympic, then the largest passenger steamer afloat.

After returning to America in 1911, and while continuing, of course, in his post at Johns Hopkins, Wood started a series of experiments with Professor Pickering of the Harvard Observatory on a new method of determining velocity of stars by photographing their spectra with an objective prism. These were very dramatic and involved the photography of entire groups of stars through a filter consisting of a glass cell filled with liquid — a solution of a chemical with the beautiful name of neodymium. This gave an additional absorption line in the spectrum of each star, from which calculations could be made of stellar velocities as stars approached or receded from the earth.

This was one of Wood’s great contributions to astrophysics, a subject in which he has figured prominently ever since. The Wood-Pickering procedure continues to be used as one of the standard methods of measuring stellar velocity — though Wood today has a new method brewing which Harlow Shapley and other prominent astronomers believe may supersede all previous systems.

In the summer of 1911, Wood purchased and mounted at East Hampton a parabolic mirror of sixteen-inch aperture and twenty-six-foot focus, which he had arranged in conjunction with a large coelostat lent by the Naval Observatory. The coelostat mirror, turned by clockwork, followed the moon and kept the reflected beam horizontal and directed against the sixteen-inch concave mirror, which in turn formed an image of the moon at its focus near the coelostat where the plateholder and ultraviolet filter were mounted. Young Professor Masamichi Kimura, of Tokyo, who ranks today among Japan’s greatest living scientists, had come over to study and work with Wood on sodium vapor, and was invited to East Hampton to help with the moon photography.

During their work a curious episode occurred. Kimura had been a welcome and popular house guest for a week end, and later was residing in a near-by hotel while they continued their summer experiments. One evening they’d been planning to photograph the moon with ultraviolet light. They had set up the telescope and mirrors in the late afternoon in a field clear of buildings, out beyond the barn, and Wood said, “Come over at eight o’clock”.

The sky was clear, but between six and seven a heavy pea- soup fog rolled in from the ocean. It was summertime, but the fog was cold as well as thick. The Woods, who had been dining early, saved after-dinner coffee for Kimura and expected him to appear at the house any minute. He did not appear. About nine o’clock the fog began to roll away, and the sky cleared. A blanket of it, however, as it sometimes does toward Montauk Point, lay thick, waist-deep on the ground. Wood waded through it toward the telescope, planning to do the photography alone. As he approached the looming shelters that covered the mirrors, he saw another dark object embedded in the fog. It was the head and shoulders of the Japanese, sphinxlike in the clear, with the rest of him up to his elbows in the murk.

“Gosh”, said Wood, “how long have you been here?”

Kimura took out his watch, consulted it in the moonlight, and said, “Hoh, have been here one hour and twenty-two minutes”.

Wood doesn’t guess at the answer. Kimura was an extremely intelligent and popular fellow, and knew from experience that he was always welcome at the fireside.

Not much came of these lunar experiments (says Wood), chiefly because of climatic conditions. Dew formed on the mirrors, the clock did not drive very steadily, and there were innumerable mosquitoes, who came from all directions to see what was going on. So later in the autumn through the courtesy of Professor H. N. Russell of Princeton University, I was given an opportunity of mounting my sixteen-inch mirror at the Princeton Observatory. Professor Harlow Shapley, now director of the Harvard Observatory, was then a fellow in astronomy at Princeton, and he assisted me in handling the telescope and making the exposures.

We made photographs of the full moon by orange, violet, and ultraviolet rays, the latter bringing out the dark deposit bordering the lunar crater Aristarchus with great distinctness, while the orange-ray picture showed no trace of it. Experiments showed that when a gray volcanic rock was treated at one spot by blowing a jet of sulphur vapor against it, a thin deposit of sulphur crystals was formed which was invisible to the eye but came out black in a photograph made with ultraviolet rays. It therefore seemed probable that an extensive deposit of sulphur had been found on the moon’s surface by the new photographic technique.

The plates obtained through the ray filters could be studied to advantage by the methods employed in the three-color process of color photography. The negative taken through the ultraviolet screen was printed on a gelatin film and stained blue, the violet and orange pictures being rendered in red and yellow respectively. The three films when superposed resulted in a very fine color photograph which brought out the differences in the reflecting power of the different dark areas on the moon in a very striking manner. The prevailing tone of the darker portions of the lunar surface was olive green, but certain spots came out with an orange tone and others with a decided purple color. The dark spot near Aristarchus came out deep blue, as was to be expected.

INFRARED LANDSCAPE: A 1911 photograph made by Wood of a summer landscape in Sicily – the earliest landscape photograph with infrared light ever made. Wood also pioneered in ultraviolet-light photography.

PEGOUD UPSIDE DOWN: Wood pirouettes in the snows of St.Moritz, in the constume he designed that won first prize at the fancy dress ball.

In 1911 Wood also continued his researches with mercury vapor and detected resonance radiation in the ultraviolet region, analogous to the sodium vapor resonance at the yellow lines. The thing of greatest interest was the invention of what he termed a resonance lamp.

A thin-walled bulb of fused quartz was blown, a drop of mercury placed in it, the air pumped out, and the bulb sealed. The mercury vapor in this vacuum bulb had sufficient density at room temperature to emit resonance radiation when illuminated by the light of a quartz mercury arc, operated with weak current at low temperature. The radiation was powerful enough to make a screen of barium platinocyanide glow with a yellow light, and if a drop of mercury was supported on a slightly warmed bit of glass between the screen and the resonance lamp, the vapor rising from the drop showed as a waving, fluttering column of black smoke on the yellow background. This made it possible to design an optical apparatus that would show the slightest traces of mercury vapor in the air of the room, a matter of importance in power plants where the engines are driven by the vapor of mercury instead of by steam. The vapor is very poisonous, and a very small leak in the high- pressure boiler or engine might exist undetected until the men showed symptoms of mercurial poisoning, by which time permanent damage would have been done. Several years later the General Electric research laboratory asked Wood to design apparatus for this purpose. He went to Schenectady with drawings, but they decided not to use it, as their chemical staff had prepared a paper that would turn black when exposed to the vapor. After getting along with this for several years, they found, according to report, that the paper was sluggish in its action, and might not respond to a sudden leak before a dangerous dose of the poison had been inhaled. One of the young men in the laboratory was then given the problem of making an optical detector along the lines suggested by Wood. After he had worked a year without results, Wood was consulted by an older member of the staff. It turned out that all that had been done was to try to detect the absorption of the vapor by the light of a high-pressure, high-temperature quartz arc. Wood pointed out the foolishness of this attempt, since practically no light capable of being absorbed by traces of the vapor is emitted by such a lamp, for it is all absorbed by the cooler layer of vapor surrounding the arc proper in the tube of the lamp. They were instructed to use a resonance lamp, or an arc operated at very low temperature, and within a year the papers were full of the “electric nose” for smelling mercury vapor in the air, developed by engineers of the General Electric Company. It was identical with Wood’s first suggestion, except that it was arranged to ring a bell, instead of showing the presence of the vapor by a difference of luminosity in the two halves of a circular phosphorescent screen, a mere matter of using a photoelectric cell and amplifiers.

In the early part of 1913, Wood was invited by Sir Oliver Lodge, chancellor of the University of Birmingham, England, to attend the annual meeting of the British Association in September — and to receive the honorary degree of Doctor of Laws from the university.

As they were planning to take a second sabbatical year abroad at about this time, Wood accepted the invitation and went on ahead to England, while the rest of the family proceeded to Paris.

Sir Oliver Lodge was president of the British Association that year, and the meeting was the largest since 1904. Among others who were to be presented with LL.D.’s at the same meeting were Professor H. A. Lorentz and Madame Curie. In presenting Wood for the LL.D., Sir Oliver characterized him as “one of the most brilliant and original experimental physicists in the world”.

In his own address at the meeting, Wood described experiments with resonance spectra and amused the distinguished gathering with an account of his use of the family cat to clean the spectroscope. Nature, in reporting his speech, was even more glowing than Sir Oliver had been in his presentation. A little later Frederick Soddy, subsequently professor of inorganic chemistry at Oxford, referred to Wood in the same journal as “one of modern experimental research’s greatest masters”.

Wood still found time to enjoy himself. Before he left England, he went out to the great automobile race track at Brooklands for the races, where he also witnessed a stunt that set the aeronautical world agog. Pegoud, the French aviator, was to do his new and famous act in which he not only looped the loop “outside” as well as “inside”, but actually flew upside down for a quarter of a mile. “It was a lovely autumn day”, says Wood, “and the great stadium was packed. There came the hum of a motor high up in the air and we saw the tiny aeroplane with Pegoud’s helmeted head showing above the cockpit. A loop, another and another, and then the plane flying on a horizontal path, upside down with Pegoud’s inverted body hanging by the straps. The crowd of twenty thousand came to its feet with a gasp and a prolonged ‘A-a-ah.’ The plane dived again, turning over, and sailed along right side up with Pegoud now only a hundred feet above the ground waving to the cheering and shouting spectators”. Wood was tremendously pleased with the show, and later made amusing use of his impressions.

He joined his family in Paris, and they all spent the Christmas holidays again at St.-Moritz, stopping at the Kulm Hotel. Among the guests was a rich Rumanian, M. Stolojean, whose beautiful wife, Marna, was the daughter of Rumania’s War Minister, M. Filipesco.

Before dinner every night, M. Stolojean gave a cocktail party for his own group and invited the Woods. They got along famously. Marna, Wood says, wore a new dress and a new jewel every evening, and her husband had a pocketful of gold pieces, one of which he always left on the table after signing the card. There was bobsledding by day and dancing at night. The climax was to be a costume ball at Christmas. At lunch on the day of the ball Margaret asked her father whether he was planning to go and what he would wear.

I’ll let Wood tell the story, since it’s one he likes to remember.

I replied to Margaret, “I’m not going to pay a hundred francs to rent a harlequin pajama, or three hundred francs to be an Indian prince for a night”. But Margaret kept at me to go, and I finally said, “All right, I’ll come. I’ll come as Pegoud, upside down in an aeroplane”.

“Oh, marvelous, but how will you do it?”

“Well”, I said, “my head and shoulders will be in the pasteboard fuselage. Gnome motor and propeller in front, the wings supported by my extended arms, white gloves on my feet, and a huge Frenchman’s head, helmeted and goggled, and with a thick beard, all securely fastened on upside down on my behind”.

Gertrude said, “It won’t be funny, it’ll just look like you with a mask on your behind”. But I saw the picture in my mind’s eye, dashed down to the village, and bought yards of yellow cheesecloth, got an armful of thin bamboo sticks from my ski man and a lot of cardboard, and hurried back to the hotel. By forcing Gertrude, Margaret, and Elizabeth to sew vigorously all the afternoon, and gluing and painting cardboard myself, I had the whole contraption finished by six o’clock. It cost altogether less than three francs.

M. Stolojean came in to view it after the cocktails. He danced about in delight. “You shall have the first prize. Leave all to me”, he said. “I will arrange all; the floor shall be cleared after the fourth dance, you are to stay in my room until the band strikes up the Marseillaise, I will have a claque by the door, and there will be shouts of Il vient Pegoud! Vive Pegoud! Pegoud comes! and you tear across the hall and dance a pas seul!”

“Great”, I said. “I’ll do stunts, spirals, sideslips, everything”. We’d had some cocktails. “I’ll do my celebrated whirling dervish act, in which I spin for over a minute and then walk a chalk line”.

It came off exactly as planned, and there was tumultuous applause as I did a sideslip through the door, and shrieks of laughter as I turned and the face and beard came into view. With the band crashing the Marseillaise with an enthusiasm created by many gold pieces, and the huge waxed floor completely deserted, the walls packed with standing spectators, I did things I did not imagine possible in the way of stunts. That the illusion was fairly good, I found out the next morning when shown photographs, one of which appeared the next week in the London Sketch. Later I was able to dance with the ladies, for I had constructed the wings in such a way that I could wrap them around my partner, enveloping her in the manner of a bat doing a bunny hug with a white mouse. At the end of the party, the drum rolled for silence, and the master of ceremonies, a retired English colonel, arose to announce the prizes.

“This first prize, by unanimous vote of the committee”, he roared, “goes to Pegoud”. I folded my wings around my body, bowed, and was handed a white box, which when opened disclosed a full set of garnet sleeve links, studs, collar buttons, etc. Gertrude overheard in a group next morning, “Really, my dear Lady Mary, I don’t see why they gave the prize to Pegoud, because after all it wasn’t Pegoud at all, and besides it wasn’t a pretty costume”.

Wood never brags of his great scientific achievements, but is vain as a child concerning triumphs of that sort.

He returned, with his family, to Paris, finished up his research, and sailed for home in June, 1914.