The shed and the isolation of radium chloride

Chemists would not believe in radium until they could weigh it. The school had no proper room, so the Curies were lent an abandoned shed that had been a medical school dissecting room. Its glass roof leaked; it was stifling in summer and freezing in winter, with no fume hoods, so smoky operations were done in the courtyard.

Residue came from the Austrian uranium works at St. Joachimsthal: first 100 kg as a gift, then several tons at low cost. Marie worked up to twenty kilograms of material at a time and stirred the boiling mass for hours "with a heavy iron rod nearly as large as myself." Then came the delicate part: dissolving and recrystallising radium-bearing barium chloride again and again, while iron and coal dust fell on her fractions. Pierre studied the rays; the chemistry was hers.

In 1902, after almost four years, she had about 0.1 g of very pure radium chloride and an atomic weight of 225. "One year would probably have been enough," she wrote, "if reasonable means had been at my disposal." At night the products glowed on the shelves: "The glowing tubes looked like faint, fairy lights." She called the shed years "the best and happiest years of our life."