Thursday, August 22, 2019

Émilie du Châtelet and the Foundations of Physics

Émilie du Châtelet linocut, 11" x 14", by Ele Willoughby, 2019

This is a hand-printed portrait of Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (1706-1749), a natural philosopher, mathematician and physicist, inspired by contemporary portraits, and shows her along with her diagrams. Each 11" x14" (27.9 cm x 35.6 cm) linocut print is printed on lovely, delicate, Japanese paper. The diagrams are from Principes Mathématiques de la Philosophie Naturelle, a two-volume translation and commentary of Newton’s Principia, published in 1759 in French in Paris.

While historically she was merely remembered as Voltaire's lover, she in fact was not only responsible for all his ideas about physics but was the first to postulate the conservation of total energy (which includes kinetic and other forms of energy combined). Further, she found the relationship between kinetic energy, mass and velocity of an object. Before translating Newton, she published her magnum opus Institutions de Physique (or Foundations of Physics) in 1740 and within a mere two years it had been translated into many languages and republished. Debate raged at the time about how the measure the force of an object and how to formulate conservation principles. She was an active participant in this dispute known as the vis viva debate. There was a schism between the Newtonians in England and the continental philosophers who followed Leibniz, particularly in German-speaking regions; she wanted the best of both while contemporaries viewed Newton and Leibniz' work as fundamentally opposed interpretations of the world. Institutions de Physique covered philosophy, space, time, matter, laws of nature and gravity including Galileo's results and Newton's more general work. In Principes Mathématiques de la Philosophie Naturelle, she combined Newton's text with Leibniz' more elegant formulation of calculus, pushing physics forward. She was recognized during her lifetime by the greatest thinkers of the day including renowned mathematicians such as Johann II Bernoulli and Leonhard Euler, her works were translated into other languages and discussed in scholarly journals and represented in (or even plagerized by) the Encyclopédie of Denis Diderot and Jean le Rond D'Alembert. She made a large impact on contemporary physics and philosophy.

Fronstispiece from Algorotti's
Il Newtonianismo Per Le Dame, 1737 Venice
After much goading and many years, Newton finally published the bulk of his understanding of mechanics and his famous three laws in Philosophiæ Naturalis Principia Mathematica, known simply as the Principia, in 1687 with two further corrected editions in in 1713 and 1726. As the title implies, the text is written in Latin. Though he had to derive the concepts of calculus to complete the work, it's largely absent from the text in favour of the geometrical approaches to infinitessimal calculus. So Émilie du Châtelet's work does not simply represent a translation - she reorganized the work using Leibniz' calculus, wrote commentaries and explanations and most importantly, added her own discoveries about kinetic energy. To this day, du Châtelet's version is the standard French translation of the Principia and modern translators still rely on Émilie's translation.

She taught herself mathematics, and then was tutored in algebra and calculus by Moreau de Maupertuis, a member of the Academy of Sciences (who had been trained by mathematician Johann Bernoulli, who also taught Leonhard Euler).  Then she turned to his protégé mathematician Alexis Clairaut, author of Clairaut's equation and Clairaut's theorem, who became a life-long friend, and other top French mathematicians. On one occassion she was ejected from Café Gradot, where men held intellectual discussions, for being a woman. So, she had some men's clothing made and boldly returned. She became a world authority on Newtonian mechanics, at a time when few imagined a woman capable or even interested in such a thing. Émilie's impact on continental physics, and bringing Newton's Principia to Europe (and to those in England more able to read French than Latin) cannot be overstated.

She was aristocrat who not only dedicated herself to knowledge, writing about physics and experimentation, she enjoyed clothing and could be extravagant. She loved fashion, gambling and jewellery.  She used her mathematics ability to devise successful gambling techniques, when she needed money for books as a teen. Voltaire was known to call her Madame Newton-Pompom-du Châtelet for the pompoms she wore. His own writings on physics were written in collaboration with her and often quoted her word for word. It wasn't long before her skills and interest far exceeded his own. She had some insight into the relationship between light, colour and heat, long before a modern understanding of energy. At the time, scholars debated whether kinetic energy or momentum was the pertinent thing - we now know that both are important, yet distinct. She leaned towards Leibniz' ideas on the subject, which shows how she was at the cutting edge of contemporary physics knowledge and debate.

She translated Mandeville's The Fable of the Bees into French and used the preface to denounce the prejudice that prevented women from access to a proper education. Nonetheless, a product of her time, she focused more on her daughter's marriage prospects and her son's education. She had to fight to be taken seriously and deal with sexism from even the well-meaning; she and contemporary part-time Bolognese physics professor Laura Bassi were not impressed when their friend Algarotti wrote a rather patronizing popularization of Newton's physics called (I wish I were kiding) Newtonianism for the Ladies. Worse, the frontispiece of his book shows a man speaking to a lady who suspiciously ressembles du Châtelet, implying he had explained Newtonianism to her. Her short-term mathematics tutor Samuel König, a student fo Mauterpuis, also tried to undermine her by claiming responsibility for Institutions de Physique. This lead to her estrangement from Mauterpuis. Ironically König later fell out with Euler and accused Mauterpuis of having plagerized him.

The story of her long-lasting relationship with Voltaire is quite fascinating, a relationship she pursued with the knowledge and blessing of her husband, Marquis Florent-Claude du Chastellet-Lomont (Châtelet is the modernized spelling of Chastellet). She first met Voltaire as a child at one of her father's salons. They became close when she re-entered society after the birth of her children. She invited Voltaire to live at their country house, a refuge for him when he was in disfavour, and there they worked together on their publications and set up a lab. They both submitted essays to the 1738 Paris Academy prize contest on the nature of fire; neither won (they lost to Euler) but they both earned honourable mention and their essays were published by the Academy. Hence, du Châtelet because the first woman to have a scientific paper published by the Academy. Eventually their relationship became a comfortable, platonic collaboration. At age 42, she began a new affair with the poet Jean François de Saint-Lambert. She feared she could not survive her subsequent unplanned pregnancy. Six days after the birth of a daughter, on 10 September 1749, at Lunéville, she suffered a fatal pulmonary embolism. Voltaire, her husband and final lover Saint-Lambert were all at her bedside with she died.

Project Vox, Duke University, accessed August, 2019
Émilie du Châtelet, Wikipedia, accessed August, 2019
Philosophiæ Naturalis Principia Mathematica, Wikipedia, accessed August, 2019
Robyn Arianrhod, Seduced by Logic: Émilie du Châtelet, Mary Sommerville and the Newtonian Revolution, Oxford University Press, 2012
Cynthia J. Huffman, Mathematical Treasure: Émilie du Châtelet’s Principes Mathématiques, Convergence (January 2017)

Thursday, August 15, 2019

Ancient Korean Astronomer Queen - Queen Seondeok of Silla

Queen Seondeok of Silla, linocut with chine collé, 9.25" x 12.5", 2019 by Ele Willoughby 
This handprinted lino block print is a portrait of Queen Seondeok of Silla or 선덕여왕 sometimes written Sonduk or Sondok (c. 595 ~ 610 - 647), reigned as 27th ruler of Silla, one of the Three Kingdoms of Korea, from 632-647, who brought about a rise in Buddhism and a renaissance in culture and science as well as building the Cheomseongdae moon and star-gazing observatory. Each print is printed on Japanese papers, and is 12.5 inches by 9.25 inches (31.7 cm by 23.5 cm).

Known for her intelligence, wisdom and benevolence, stories survive of her curiosity and cleverness even as a child. When her father the King was gifted peony seeds and a painting of peonies from China she remarked that it was a pity the lovely flowers had no scent. The astonished adults asked her how she knew; she had noted that the painting of the flower did not show bees or butterflies and had corrected deduced that they were unscented. One story recounts how she predicted an attack from the neighbouring Baekche kingdom by noting the sounds of frogs at the gate.

She was introduced to astronomy by her tutor and tried to discuss it with the Chinese ambassador but was rebuffed as Confucianism discouraged educating women. Then she predicted the occurrence and duration of a solar eclipse which angered him and he persuaded her father to stop her studies. Seondeok wrote the following on a votive jar dedicated to her grandmother:

Will I ever know the truth about the stars?

I’m too young to engage in theories about our Universe.

I just know that I want to understand more. I want to know all

I can. Why should it be forbidden?*

But when her father died without a male heir she became Queen as the first female sovereign in ancient Korea. During this turbulent time, the southern Korean peninsula was divided into three competing kingdoms of Silla, Goguryeo and Baekche and Seondeok was able to combine diplomacy, forging alliances with Tang China, with military might to weather rebellion and threats from other her neighbours during her reign. After lifting peasants’ taxes for a year and helping orphans and elderly, she set to work building a 9m tall moon and star-gazing tower Cheomseogdae. The bottle-shaped stone observatory still survives today, and is the oldest standing observatory in East Asia, and perhaps the world. The capital became a centre of culture and science; mathematics, astronomy and astrology flourished. The observatory is believed to have been the centre of an entire scientific district.

The building itself represented knowledge; the number of stones represents days of the year (scholars differ on whether it contains 362 or 365 large stones representing days in the solar or lunar year). The stones appear in 27 courses (for Seondeok, the 27th ruler) with 12 courses above and below the window entrance for the months of the year and these sum to 24, the number of solar terms in a year (24 points in traditional East Asian lunisolar calendars that matches a particular astronomical event or signifies some natural phenomenon). Including the stylobate, or platform on which it was built, gives 28 courses and 28 symbolizes the 28 constellations of East Asia. The addition of the two-tier top brings us to 30, the number of days in a month. The tower itself is a gnomon of a sundial and the window captures the sun’s rays on the interior floor at spring and autumn equinoxes. Astronomy was of vital importance as it governed agriculture and contemporary scientists produced detailed star charts. Astrology influenced political decisions of the day. Thus observations at Cheomseongdae were of utmost importance to Silla.

*Gabriella Bernardi, 'The unforgotten sisters: Sonduk, the astronomer queen.' Cosmos magazine, 28 March 2018

Hong-Jin Yang, 'Historical Astronomy of Korea', Korean Astronomy Olympiad, Korean Astronomical Society, 2012

K.P.Kulski, 'The Tower of the Moon and Stars: Queen Seondeok of Silla,' Unbound, 2017

Mark Cartwright, Cheomsongdae, Ancient History Encyclopedia, 2016

Mark Cartwright, Queen Seondeok, Ancient History Encyclopedia, 2016

Queen Seondeok of Silla, wikipedia, accessed August, 2019

Cheomseongdae, wikipedia, accessed August, 2019

Category of Astronomical Heritage: tangible immovableCheomseongdae observatory, Republic of Korea, UNESCO Portal to the Heritage of Astronomy, accessed August, 2019