In late September Wood went with his wife and daughter Margaret to San Francisco, their first visit with the grandparents since before the earthquake in 1906. Wood immediately went down to Pasadena and was quartered in the so- called “Monastery”, the sleeping quarters of the observatory staff on Mount Wilson. The sixty-inch telescope was assigned to him for four evenings, and, to his delight, he found Harlow Shapley, who had assisted him in Princeton, now a member of the staff and ready to help him again. The bromine cell was mounted on a brass frame directly in front of the plateholder, which covered an aperture in the side of the great tube near the top, the huge mirror of “silver on glass” being at the bottom of the tube. Photographs of Jupiter and Saturn were made with infrared, yellow, violet, and ultraviolet light, the latter showing an equatorial belt on Saturn that had never been seen before, the cause of which gave rise to considerable discussion among astrophysicists. It was finally decided to be a circular cloud of very fine dust that bordered the “ring” on its inner edge.
As this research neared its end, a “terrible” tragedy occurred.
We had cleaned and charged the cell with fresh bromine vapor (Wood says), leaving as usual a drop or two of the liquid to make up the loss due to its slow combination with the beeswax cement. One of us had clamped it in position, and the great telescope was slowly swung into its nearly vertical position. Suddenly there was a crash like that made by a glass bottle shattered on a cement floor. “Good God”, we both (I think) gasped. “The bromine cell on the silver mirror”. I leaned over the edge of the tube and looked down. Sure enough, on the great circular shining silver surface, five feet in diameter and twenty-five feet below me, there was a large irregular black splotch, some eighteen inches across. There was nothing that could be done at the moment, and I was relieved to see that the spot was not spreading, which indicated the bromine had all been used up. But had the glass surface been damaged? That was the question that caused a sinking feeling in the pit of my stomach. Shapley said that it was his fault, as he believed he had attached the cell, but I insisted (I hope) that it was mine, as I felt sure I had done it. However, it turned out all right: the glass mirror was not damaged, they were planning to resilver it anyway in a couple of weeks, and the amount of silver removed had not caused enough loss of light to interfere with the program arranged for the intervening time. We felt better when told by the director that worse things than this had happened. One of their mechanics had once let a small monkey wrench fall on the mirror, which made a large nick in the surface.
Returning to Baltimore late in October, he started a new line of investigation with Professor Okano, a Japanese scientist who had been sent to work with him. They investigated what is known as the “ionizing potential” of sodium vapor, which had never been determined. Defined in words, they were to determine the lowest voltage that would cause sodium vapor to glow or emit light in a vacuum tube. The final result was interesting, though they did not feel sure of it until a number of sources of error had been discovered and conquered. A sodium lamp could be operated with an electric potential of only 1.5 volts on its terminals or by one dry cell, provided free electrons were present. Wood had, in 1910, in collaboration with R. H. Galt, one of his students, studied the spectra of the electrical discharge in dense sodium vapor, and been struck by the overpowering brilliancy of the yellow light in some cases. “It was like looking at the sun through a yellow glass”, he says. He had dreamed of sodium lamps, naturally, but at the time there was no way of preparing a glass tube or bulb that would not blacken and become opaque after a few minutes’ exposure to the corrosive vapor. It was this circumstance that had caused Lord Kelvin to ask, “Have you succeeded yet in taming sodium vapor?” Modern sodium lamps are of course the latest development for street lighting.
Chapter Fourteen.
Wood Joins the Army as a "Sheep in Wolves’ Clothing” and Becomes "a Hell of a Major” Overseas
Sheep in wolves’ clothing” is the name Wood applied to himself and other professors and scientists who were given commissions and uniforms in the World War. Long before we entered it, he’d been helping the War Department with technical advice, and he kept trying in vain to get his friend General Squier, Chief Signal Officer of our Army, to give him a commission and send him overseas. Then came a cable from Paris to the State Department, rubber-stamped by Prime Minister Ribot, requesting that Wood be commissioned and sent to Paris to work in collaboration with the French scientific group that formed the Bureau of Inventions.
“I was in East Hampton at the time”, said Wood, and though I (the biographer) have taken two or three shots at trying to tell what happened next, I think it’s best and safest to let him go on telling it in his own way.
I had to go down to Washington (says Wood) to take my medical examination and go through all the formalities. I irritated the Medical Corps sergeant who was testing me on eyesight. When he was giving me the test for color blindness and took out a box of different colored pieces of yarn, he produced a red piece and asked me, “What’s this?” I answered, “Worsted”. But in spite of this, I managed to finish the physical examination and returned to East Hampton to await orders. After I had been there awhile, I received a communication from the War Department ordering me to report to Washington again for a mental examination.
I thought this a bit strange, especially as the head of the Signal Corps, for which I was being examined, was General Squier, an old Johns Hopkins man, who should, I thought, be able to vouch for my mental qualifications. So I wrote a letter to Squier. This was answered by some captain who told me in rather brusque terms to do as I was ordered. Squier said afterwards, “You should have written to me at my apartment. I never even saw your letter”.
This meant another trip to Washington, where the temperature was something like 101° in the shade. At the end of this rather long and expensive trip, I presented myself in front of a fat man, who gave me a mental examination, which, as I remember, consisted of the following dialogue:
Q. “What is your name?”
A. “Robert W. Wood”.
Q. “What is your occupation?”
A. “Professor of Physics at Johns Hopkins University”. “That’s all”, he said, completing the record.
This whole business naturally irritated me a good deal.
The irritation, as Dr. Wood realized and faithfully mentions, was mutual. I am informed from other sources that after the door had closed on him, an unhappy sergeant said, “I don’t care whether he’s the greatest scientist on earth, he’s going to make a hell of a major! I’d hate like hell to be his colonel”. I don’t know how much his colonel suffered, but quite a while later in the palatial diner on the Blue Train going up from Toulon and Marseille — according to Dr. Hugh Young, who was present — Major Wood was invited to meet General Pershing for the first time and have coffee with him. The commander in chief inquired what outfit Wood was with, and Wood is said to have replied, “Well, I suppose I’m what you would call a sort of free lance”. “And just what are you doing?” Pershing asked. And Wood is reported to have replied, “Well, sir, it’s supposed to be a secret, but I don’t think there’d be any harm in letting you in on it”.