Veronique Greenwood in the New York Times:
Just after Christmas of 1938, a young woman named Marguerite Perey — then 29, with a plain, open face, her eyes intent upon her work — sat at a bench in the Radium Institute of Paris, a brick mansion near the Jardin du Luxembourg. In a glass vessel, she examined fluid containing metal salts. She carefully dosed it with lead and hydrogen sulfide, then with barium, causing the solution to separate into different substances. She was in the final stages of purifying actinium, one of the rarest and most dangerous elements yet discovered, from uranium ore. Ten tons of ore yielded just one or two milligrams of actinium; Perey, who joined the institute as a teenager to be the personal technician for Marie Curie, was an expert in its isolation.
The Curie laboratory hired researchers from across Europe, but Perey was a local girl, the youngest of five children of a flour-mill owner in Villemomble, just east of the city. The death of her father had left the family in financial straits. Her mother gave piano lessons to fill the gap, but Perey had to abandon the idea of going to medical school in favor of a vocational college for chemistry technicians. The Curies often hired the top student from the school as an assistant, and Perey, at 19, was called in for an interview. She later described her first impression of Marie Curie: “Without a sound, someone entered like a shadow. It was a woman dressed entirely in black. She had gray hair, taken up in a bun, and wore thick glasses. She conveyed an impression of extreme frailty and paleness.” A secretary, Perey thought — then realized she was in the presence of Curie herself.