“As Voltaire wrote, she ‘was a great man whose only fault was being a woman'” Pictorial Press Ltd/Alamy Stock Photo

IN THE spring of 1749, Emilie du Châtelet realised to her horror that she was pregnant. She adored her two children, but was engrossed in her most ambitious project yet – translating and interpreting Isaac Newton’s Principia, his monumental book on mechanics and gravity. Childbirth was always a hazardous affair – one of her three babies had died – but at the age of 42 she knew that it would be particularly perilous. It was a race against time to finish her work.

More than 60 years had gone by since Newton published his revolutionary cosmology, but in France his ideas remained controversial. Convinced that reason and mathematics could unlock the mysteries of the universe, du Châtelet was determined to persuade her compatriots that a single force of gravity tied the universe together. She counted the months and then the days, working long into the nights and plunging her hands into ice-cold water to keep herself awake. A few days before giving birth, she completed her manuscript, triumphantly noting down the date. She died just days later; her baby daughter soon followed.

Until recently, if du Châtelet was mentioned at all, it was as Voltaire’s mistress rather than as a talented mathematician in her own right. At a time when women were largely excluded from scientific debates, she earned respect across Europe. In books and articles she critiqued the theory of the French national hero, René Descartes. While he envisioned the planets swirling within clouds of tiny invisible particles, Newton’s cosmos …