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

While the sodium vapor investigation was in progress I was at work on several other problems, one having to do with the remarkable optical properties of a chemical with a terrifically long name, nitrosodimethylaniline, which was one of the substances we had been required to make in Professor Remsen’s course in organic chemistry ten years before. It had struck me at the time that the bright green flakes with a metallic luster looked interesting, and I had preserved the material in a bottle. In the course of my lectures at Madison I had come to the subject of anomalous dispersion, shown by substances having strong absorption. A prism made of such a substance produces a spectrum in which the colors are not arranged in the same order as they are in the rainbow or in a spectrum formed by a glass prism, the deviation being greatest, but in opposite directions, for the colors close to and on either side of the absorption band. This phenomenon had previously been demonstrated and studied by solutions of aniline dyes contained in a hollow prism of glass. It had occurred to me that if I could fuse the pure dye and press it between two pieces of plate glass inclined at a small angle to each other, a much greater effect would be produced. I tried it with some crystals of cyanine, the dye used for sensitizing photographic plates for infrared rays. They melted easily and made beautiful prisms, which gave the effect in a greatly enhanced degree. Trials then made with about fifty other dyes showed that all were useless; they decomposed and swelled up into a spongy black mass without fusing, and I have never been able to find anything else that answered the purpose. Even cyanine made by other chemical plants would not melt. My sample was what horticulturists would term a “sport”, I suppose. Ehrlich had 605 failures before the successful 606th. I had one success followed by fifty failures! In looking over my preparations made years before in Remsen’s course I ran across the nitrosodimethylaniline green flakes. These green flakes melted at low temperature and gave beautiful prisms, which transmitted the red, orange, yellow, and green rays in normal order but gave a spectrum fifteen times as long as the spectrum produced by a glass prism of equal angle. Moreover, in solution, the substance absorbed the violet rays powerfully but transmitted the ultraviolet, and by combining it with dense cobalt-blue glass I obtained something that had been searched for in vain — a ray filter that would be opaque to visible light but transparent to the ultraviolet. With this filter I made my first landscape and lunar photographs in ultraviolet light, and at the autumn meeting of the National Academy in Baltimore in 1902 I gave an experimental demonstration of what could be done with what is now called black light.

The meeting was held in the lecture room of the physical laboratory, and after the exhibition of various photographs made exclusively by ultraviolet light, the room was completely darkened and the invisible rays from an arc lamp in a light-tight iron box were passed out through a single window made of the filter combination opaque to visible light. A white porcelain plate held in front of this window was invisible. The rays were brought to a focus by a large condensing lens on a pile of crystals of uranium nitrate, which immediately glowed with a brilliant yellow-green light, of sufficient intensity to read by. Newspaper accounts of the meeting record that this experiment “was received by a burst of applause, a reception rarely accorded at dignified Academy meetings”.

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Wood never denied himself the chance to make grandstand demonstrations such as this, but he didn’t let them interfere with his laboratory research. During 1902 alone ten scientific papers of his appeared in the Philosophical Magazine; and a German physicist wrote to an American friend at this time, “Wood — he produces like a rabbit”.

In the summer of 1902 the Woods all went to San Francisco to visit Gertrude’s parents, who had sold the house in Ross Valley and reopened their house at 1312 Taylor Street. A new addition to the family was expected about the middle of July, and Gertrude insisted that this was the obvious time for Robert to visit the Hawaiian Islands, where he had always wanted to go because of his father’s early life there. Wood’s protests against the infamy of a husband deserting his wife at such a time were pronounced “rubbish” by Gertrude, who finally persuaded him to abandon her. She would be perfectly all right with her mother, nurse, and the doctor to take care of her. In those days you always had your babies at home. Maternity hospitals were an unknown luxury.

Wood says: