Marie Curie - Kathleen Krull [12]
She came up with a hypothesis, a possible explanation that could be tested. A new element, considerably more active than uranium, must be present in the ore. She set out to look for an unknown substance of unusually high activity. “The element is there and I’ve got to find it,” she told Bronia. She was doing something completely new, looking for an unknown element with the only clue to its existence being its strange rays—rays that she called radioactive, meaning active in emitting rays.
To Marie, time was of the essence. “I had a passionate desire to verify this hypothesis as rapidly as possible,” she wrote. She was aware of other scientists working in this area already, though perhaps not as precisely and systematically as she was. G. C. Schmidt in Germany, for example, was investigating the activity of thorium. There was a race on—all terribly polite, but still . . . Marie was determined to be first.
At this point, Pierre showed what a generous spirit he had: he could see his wife was on the verge of discovering something major. As brilliant as he was, Marie’s work was leading in a more important direction. For a man raised in the nineteenth century, when the second-place status of women—both intellectually and physically—was a given, Pierre did something extraordinary. He stopped his work on crystals and joined her. Marie, who had something of a notebook obsession, had all along been keeping rigorous records of her work. Now her meticulous handwriting was interspersed with his childlike scrawl.
Isolating this theoretical new element involved a process of elimination. All other elements in the pitchblende had to be separated out chemically. After weeks of attacking and reattacking their supply of pitchblende with all the chemicals available to them, the Curies produced something they suspected was their new element.
How could they prove it? Possibly by looking at the light pattern produced by the substance. during Newton’s famous 1666 experiments, he first worked with sunlight and a prism, proving that light contains all the colors. By Marie’s time, a whole science—spectroscopy—had developed. In spectroscopy, when an element is heated to a gaseous state and the light it emits is studied through a prism, it produces unique lines along the spectrum of colors. The pattern of spectral lines supplies a sort of signature for that element. Already, eight new elements (including helium) had been identified through their unique spectral lines.
The Curies called in Eugène demarcay, a French spectroscopy specialist, to help. Alas, no unique spectral lines appeared when their substance was tested. Whatever they had could not be labeled a new element . . . not yet.
As usual, Marie was undeterred. It was her hunch that the substance just needed more purification. After more chemical investigation, on July 13, 1898, she had what she wanted. A new element. She felt secure enough to give it a name—“polonium,” with the abbreviation “Po.” Pierre wrote it down in their notebook. Patriotic Pole Marie came up with the name to honor her native land.
Five days later, at the French Academy, Henri Becquerel himself read a report by the Curies, called “On a New Radio-Active Substance Contained in Pitchblende.” (Pierre couldn’t read it because he wasn’t a member, either.) It announced the Curies’ discovery of polonium, a substance well over four hundred times as radioactive as uranium—a new element. It was also the first use of “radioactive” in print. She wrote that it was “necessary at this point to find a new term to define this new property of matter.” She had discovered a new element in a completely new way—by its rays.
The scientific establishment understood it was not dealing with an amateur. Marie was awarded a prize, money, and a statement that conceded, “The research of Madame Curie deserves the encouragement of the Academy.”
At long last, the Curies took a three-month summer vacation to get out of the hot city. Talk and planning did not cease, especially a hunt for a supplier of enormous amounts of