Marie Curie: two Nobels, and the method behind them

Maria Skłodowska was born in Warsaw on 7 November 1867, the fifth child of a family of teachers, in a Poland under Russian rule. The city’s universities did not take women: to study, you had to leave. With her elder sister Bronia she made a pact, one working while the other studied, then the other way round. She was a governess for several years before her turn came.

When did she reach Paris? The sources disagree, and it is worth saying so: the Musée Curie has her enrolling at the Sorbonne in October 1891, but in a note to her own book she writes that she came in 1892. What follows is dated: a degree in physical sciences in 1893, in mathematics in 1894, and that year a meeting, Pierre Curie. They married on 26 July 1895.

It starts with a discovery nobody did anything with. In 1896 Henri Becquerel noticed that uranium gives off invisible rays. It was noted, and left there. Marie Curie made it her thesis subject and asked the question the others had not: how much? With the Curie electrometer and its piezoelectric quartz, built by Pierre and his brother Jacques, she measured ore after ore, and pitchblende turned out to radiate far too much for the uranium it contains.

What follows is the heart of her work, and she wrote it down plainly. In the autobiographical notes she wrote for the English edition of her book: “The method we employed is a new method in chemical research based on radioactivity.” You separate, you measure what you have separated, you keep the most active fraction, you start again. At the end of it, two elements: polonium, announced on 18 July 1898, and radium on 26 December.

They still had to be got out of the ore. Tonnes of residue arrived from the mine at Sankt Joachimsthal, in Bohemia, into a shed at the School of Physics and Chemistry on rue Lhomond. There, in her own English, they “worked practically unaided during two years”; she had to “work with as much as twenty kilogrammes of material at a time”, and to stir “for hours at a time, with an iron bar, the boiling material in the cast-iron basin”. They expected at most one per cent of new substance; the real proportion “did not reach even a millionth per cent”.

The two prizes do not reward the same thing, which is why there are two. The 1903 physics prize went half to Henri Becquerel, in the Nobel Foundation’s words, “in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity”, and half jointly to Pierre and Marie Curie “for their joint researches on the radiation phenomena discovered by Professor Henri Becquerel”. Radium is not named in it. Marie Curie was the first woman to receive a Nobel Prize.

The 1911 chemistry prize is hers alone, and it names what the first had left out: “the discovery of the elements radium and polonium”, “the isolation of radium and the study of the nature and compounds of this remarkable element”. Between the two prizes she lost Pierre, run over by a horse-drawn wagon on the rue Dauphine on 19 April 1906, and took over his course at the Sorbonne. In 1908 she became the first woman university professor in France.

The year of the second Nobel was no triumph. In January 1911 she stood for the Académie des sciences and was not elected. In November the press revealed her relationship with Paul Langevin and set off a violent xenophobic campaign against her. The prize came in December.

She left a book. In Pierre Curie, published in French in 1924 and in English the year before, she describes the laboratory from the inside. The shed first: “a wooden shed with a bituminous floor and a glass roof which did not keep the rain out, and without any interior arrangements”.

In the evening they came back to look at their vessels: “from all sides we could see their slightly luminous silhouettes, and these gleamings, which seemed suspended in the darkness, stirred us with ever new emotion and enchantment”. What that light was doing to them, nobody yet knew.

And then there is what they decided. When the radium industry started up, the Curies gave up any profit from it: “We took no copyright, and published without reserve all the results of our research, as well as the exact processes of the preparation of radium.” The Kelloggs’ English says copyright where her French says brevet, a patent, which is what she meant and what they did.

The war of 1914 arrived just as she was finally getting a real laboratory, the Institut du radium, whose Curie pavilion was built between 1912 and 1915. She left it at once: with the Red Cross she had eighteen radiological cars fitted out to X-ray the wounded near the front. The nickname petites Curie came later, from her daughter Ève, in the book she wrote about her mother.

She died on 4 July 1934 at the Sancellemoz sanatorium, of an illness identified at the time as pernicious anaemia, after more than thirty-five years of handling radioactive substances. Her ashes and Pierre’s entered the Panthéon on 20 April 1995: she is the first woman honoured there on her own merits. What she leaves is not only two elements, it is a reflex: faced with what nobody is looking at, measure.