Inspiring STEM Women: Sophie Germain

Sophie Germain was a French mathematician, physicist and philosopher. She was born in Paris in 1776 and was one of three daughters to a fairly wealthy Parisian milk merchant. In 1789 the Bastille fell in France. This was widely regarded as the most iconic event of the Revolution. The family spent an increasing amount of time indoors to avoid the political unrest and the rebellious atmosphere in their town. Sophie looked to her father’s library for entertainment and it was here that she read a copy of her father’s J.E Montucla's 'L'Histoire des Mathématiques'. Sophie was particularly inspired by the story of the death of Archimedes. His passion for geometry prompted her to begin her own studies on the subject. Furthering her use of her father's library, Sophie taught herself Greek and Latin to enable her to read complex geometry, such as that of Newton. Her parents were unimpressed with Sophie’s interest in Mathematics, as studying it was seen as an entirely inappropriate interest for a woman. To keep her from studying in secret her parents would remove warm clothes at night and prevent her from having a fire or any candles, but they would find her ‘asleep at her desk in the morning, the ink frozen in the ink horn and her slate covered with calculations.’ (Lynn Osen)

Sophie’s passion for Mathematics grew throughout her childhood. 1794 saw the opening of École Polytechnique, a French public intuition of higher education and research. Women were forbidden to attend but their new education system made lecture notes available to anyone who requested them, as well as allowing any students to submit written observations. Desperate to contribute her ideas Sophie took up a male pseudonym through a previous student, 'M. leBlanc' and began to send her work to a faculty member, Joseph Louis Legrange. Joseph was so impressed by the work of M. leBlanc that he insisted on meeting him. When Legrange discovered LeBlanc’s true identity was actually Sophie he became her mentor and would visit her at home to offer his moral support to her studies. 

Sophie took an interest in number theory after reading Carl Gauss' 'Disquisitiones Arithmeticae' and remarkably took to exchanging letters with Carl Gauss, one of history’s most famous mathematicians, all the time writing under the name 'M. LeBlanc'. Gauss was shocked when he discovered Sophie’s true identity. He replied to her saying, ‘How can I describe my astonishment and admiration on seeing my esteemed correspondent M leBlanc metamorphosed into this celebrated person. . . when a woman, because of her sex, our customs and prejudices, encounters infinitely more obstacles than men in familiarising herself with [number theory's] knotty problems, yet overcomes these fetters and penetrates that which is most hidden, she doubtless has the most noble courage, extraordinary talent, and superior genius shocked when he discovered her true identity.’ Despite their friendship Gauss did not review most of the works he sent to him and his replies were often delayed. When his own interests shifted from number theory in 1809 they ceased to write letters. 

Sophie’s interest began to move from number theory to the area of applied mathematics. The Institute de France, a French learned society, set a completion asking for the mathematical theory behind the elasticity of metal plates based on an experiment carried out by Ernst Chaladni. Sophie was the only one who entered the competition and while her theory was flawed, her approach was correct. The competition was extended by two years and she won the prize on her third attempt. She then submitted her third paper under her own name to Paris Academy of Sciences and became the first woman to be awarded a prize from the Academy. Despite her victories Germain continued isolated because of her gender, being described as ‘always on the outside, like a foreigner, at a distance from the professional scientific culture.’ Germain had won the contest yet was still not allowed to attend the Academy sessions because the academy excluded all women aside from the wives of other members. It was only when Sophie met Joseph Fourier, a secretary of the Academy, seven years later that he gave her tickets. In 1821 Sophie published her prize winning essay in which she addressed some of the errors in her method. After submitting a revised version of the essay to the Academy in 1826 they felt they were put in an uncomfortable situation. They did not rate the work highly, dismissing it as 'inadequate and trivial' however the Academy also did not want to reject it, as they would be treating her the same as a male colleague. Instead, despite their opinion, they recommended Sophie to publish her trivial revised version, which she did.

Sophie’s work in applied mathematics was impressive yet her most astonishing work was in number theory, most significantly in relation to Fermat’s Last Theorem. In 1815 the Academy offered another prize competition, this time it was to provide proof of Fermat’s Last Theorem. Sophie wrote to Gauss despite them not having spoken for ten years to ask him to review some of her work, he never responded. Sophie’s work on Fermat’s last Theorum, commonly referred to as 'Sophie Germaine’s Theorum' was astonishing, both in the theorem itself and in the counter examples to Fermat’s Theorum. She never published her work and it was only recognized when Legende put it in the footnote of his treatise on number theory, having used it to prove Fermat’s Last Theorum for p=5. 

In 1929 Sophie was diagnosed with breast cancer, but as ever her passion was unaffected and she continued to produce an exceptionally high standard of work.  She published ‘Annales de chimie et de physique’, a paper on the curvature of elastic surfaces and an examination of principles which lead to the discovery of the laws of equilibrium and movement of elastic solids. Her works has been since expanded and built upon and her innovative theories and approaches opened new ways to approach mathematical problems. Without her work on elasticity, the Eiffel Tower could not have been built. Indeed, her work is the basis for the modern building. Sophie Germain died in 1831, on her death certificate she was not listed as a scientist or a mathematician, but a ‘rentière – annuitant’, a property holder. A woman of no profession.

Since her death she has been given various honours including name honours in number theory and since 2003 there has been the Sophie Germain Prize awarded annually by the Academy of Sciences in Paris.

Written by Sophie Chadwick 



Carl Gauss

Sophie Germain

The Royal Academy of Sciences 


Posted on Tuesday Apr 26