Books- Voltaire and the woman who corrected Newton
David Bodanis’ book Passionate Minds relates to one of the most fascinating stories about Voltaire. It concerns his relationship with a woman who until recently had disappeared from history- Emilie du Chatelet, the woman who got Newton’s gravity equation into its modern form. This was the age of the “Enlightenment” in pre-revolutionary France. Book printing was potentially dangerous, and offending France’s venal aristocracy was likely to be painful.

Voltaire is well known for his various clashes with the French social order, and it’s an irony that perhaps the only person ever to pose a real foil for Voltaire on an intellectual level was a female aristocrat. Du Chatelet was unique in terms of her mental attributes, and was a virtual outcast in the brainless circles of French aristocracy for that reason. She eventually married the Marquis du Chatelet, and settled uncomfortably into the environment of vacuous entertainments of her class. Meeting Voltaire, however, changed all that, permanently.

The meeting of these two minds resulted in an affair lasting over a decade. Affairs were common, and as long as no embarrassment was suffered by the nobles concerned, all was well. Voltaire and Emilie moved into the dilapidated Chateau de Cirey in Champagne and completely refurbished it. Emilie’s exposure to Voltaire soon gave her the confidence to reassert her original mental character. With some of the inevitable bumps of any relationship, Voltaire discovered that he’d met an extraordinary woman, certainly the most important woman in his life.

Voltaire was probably secretly as amused as aghast to find that his beloved Emilie was a prodigy in mathematics. It’s a testimony to Emilie’s effect on Voltaire that at one point they were competing with each other for a science prize. Voltaire, who could and occasionally did breeze through life with a few quips, and was evasive enough when it suited him, was actually challenged intellectually. They came in neck and neck in the prize awards. Voltaire had spared no expense, Emilie had used her mind and an upstairs room with a lens.

The relationship with Voltaire eventually ended, but Emilie was still working on her mathematics, despite a turbulent personal life and pregnancy. The study of Newton was the work of the true scientists of the day, and it was ultimately Emilie who discovered that Newton’s formula for gravity was flawed, and correlated the results of a range of experiments into a formula. She was the one who put the “squared” into the modern equation. That formula was the original basis of E=mc2.

Her findings were published in a booklet printing under the title Principes Mathematiques de la Philosophie Naturelle. Interestingly, while Emilie’s name faded from memory, her mathematics became (and still are) the accepted formula. The book was completed literally days before her death from childbirth.

Passionate Minds is one of those rare books which should not be put down at all. The relationship, conducted in the midst of Voltaire’s own extraordinary life, makes a mockery of fiction.  Bodanis, whose works include the history of E=mc2, is an appropriate person to write this long overdue vindication of one of history’s most brilliant women. Voltaire grieved for her for the rest of his life.