Georges-Louis Le Sage (; 13 June 1724 – 9 November 1803) was a Genevan physicist and is most known for his theory of gravitation, for his invention of an electric telegraph and his anticipation of the kinetic theory of gases. Furthermore, he was a contributor to the Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers. Life and education Le Sage was born in Geneva, his father, a descendant of Théodore Agrippa d'Aubigné, was Georges-Louis Le Sage from Couches in Burgundy, and his mother Anne Marie Camp. His father, who was the author of many papers on various subjects, occupied his son of his own studies early, including the works of the Roman poet Lucretius at the age of 13. According to Pierre Prévost and some notices of Le Sage, the education by his parents in his early years was very strict, and Le Sage reacted to this by isolating himself and with meditation on various subjects. Contrary to his father, who allegedly only accepted facts and had little interest in generalisation, Le Sage was primarily interested in general and abstract principles. Le Sage took the first regular education at the college of Geneva, where he was friendly connected with Jean-André Deluc. Besides philosophy, he studied mathematics under Gabriel Cramer, and physics under Jean-Louis Calandrini. Later he decided to study medicine in Basel, where he also gave private lessons in mathematics. Here, Le Sage also met Daniel Bernoulli, whose work on the kinetic nature of gases was very influential to him. Then Le Sage left Basel and continued to study medicine in Paris. After he came back to Geneva, Le Sage tried to work as a physician, but it was denied because his father was a native from France. There, he was friendly connected with Charles Bonnet. Against the will of his father Le Sage devoted his life to mathematics and, in particular, a search for the mechanisms of gravity. He tried to become a professor for mathematics in Geneva, but he couldn't get the position. Although Le Sage published few papers in his life, he had extensive letter exchanges with people like Jean le Rond d'Alembert, Leonhard Euler, Paolo Frisi, Roger Joseph Boscovich, Johann Heinrich Lambert, Pierre Simon Laplace, Daniel Bernoulli, Firmin Abauzit, Lord Stanhope etc.. He gave private lessons in mathematics, and his pupils, including La Rochefoucauld, Simon Lhuilier, Pierre Prévost, were deeply impressed by his