300 years ago: Émilie du Châtelet born in Paris

In case you are French and want to read Newton's Principia in your language instead of the obscure Latin, you can resort to a translation, Principes mathématiques de la philosophie naturelle, that has been prepared by a very remarkable woman, Emilie du Châtelet, who was born 300 years ago, on December 17, 1706.

Emilie was the daughter of an aristocrat at the court of the Sun King, Louis Nicolas Le Tonnelier de Breteuil, and had the chance of being educated at home, instead of spending the time until her marriage in a convent, as it was then the custom for girls of her family background. She was very interested in mathematics and the sciences, and managed to get lessons by a young académicien named Maupertuis, of later fame for the formulation of the principle of least action.


Gabrielle-Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (en.wikipedia.org)

For a long time, she has been known mainly as the companion and lover of the philosopher and writer Voltaire, with whom she shared many interests, literature, drama and opera, and - physics. Indeed, Voltaire had spent some time in England before, where he had learned about Newton's work and became fascinated by the simplicity of the universal law of gravitation and Newton's laws of motion. He had written about this, among many other things, in his lettres philosophiques, and was about to prepare a long, popular exposition of Newtonian physics, the Elémens de la philosophie de Neuton, when he met Émilie.

The frontispiece to Voltaire'’s Elémens de la philosophie de Neuton, with Émilie du Châelet illuminating Voltaire with the light of insight coming from Newton (Rare Books Division, New York Public Library). The Elémens saw 26 editions between 1738 and 1785 and contributed enormously to the popularization of Newtonian physics in France.

Praise of England in the letters philosophiques had stirred some trouble for Voltaire in Paris, so he was especially happy when Émilie invited him to her husbands manor, the Château de Cirey, far away from the capital, and close to the border of Lorraine, which was not part of France at that time.

At Cirey, they spent happy and very creative and productive years together. They established a small theatre in the castle, and a physics laboratory. Here, they conducted experiments on the nature of fire, preparing contributions to a contest organized by the French Academy of Sciences.


The Château of Cirey-sur-Blaise in eastern France ((www.trekearth.com)

Émilie continued her studies of maths and physics, under the guidance of Clairault and the German mathematician König. She started to write a textbook on physics intended for the education of her 12-year old son. The result, the Institutions de physique, was praised as an excellent exposition, but over the head of most of its potential readers. It contained a discussion of Leibniz ideas and his concept of vis viva, the living force, which we know today as the kinetic energy. It's hard to imagine now that it took several decades of intense debates before the concepts of conservation of linear momentum and kinetic energy in simple mechanics were neatly formulated and firmly established. Anyway, Émilie's exposition of what we now call kinetic energy, the quantity proportional to the square of the velocity - is the reason that she is marketed sometimes as a direct precursor of Einstein and his famous formula E = mc².

In 1745, she embarked on her largest scientific project - the translation of Newton's Philosophiae naturalis principia mathematica, based on the third Latin edition from 1726. She managed to finish this tedious work just days before her death, too early and under quite dramatic circumstances in September 1749.

I find it difficult to gauge her scientific achievements, not the least because of the big time lag since the days of the enlightenment. She didn't contribute lasting original research, it seems, but her expositions and writings most probably was instrumental in the shift of the center of gravity in mathematics and physics from Newton's England to France - Laplace, one of the most prominent of the French mathematicians of that time, was born in the year she died. Anyway, La Marquise du Châtelet was a very remarkable woman, and her life demonstrates in a wonderful way how science can be and should be part of general culture.


In France, at least, it seems that she has become kind of a celebrity at last, honored at her tricentennaire as the first woman scholar - there is even a nice children's book about her.

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There are several places on the Web to read more about Émilie du Châtelet, e.g.

• Gabrielle Émilie Le Tonnelier de Breteuil Marquise du Châtelet at the MacTutor History of Mathematics archive


• Émilie du Châtelet: the genius without a beard by historian Patricia Fara in Physics World June 2004


• Ancestors of E = mc² in the NOVA Einstein's Big Idea program

Passionate Minds by David Bodanis is a recent biography about her.


About the vis viva controversy, there was an article in the October 2006 issue of Physics Today, see e.g. here.

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TAGS: Émilie du Châtelet, Mechanics, History