Georges-Louis Le Sage
Georges-Louis Le Sage (French: [lə saʒ]; 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. He was a contributor to Diderot's Encyclopédie.[1]
Georges-Louis Le Sage
13 June 1724
9 November 1803 (aged 79)
Life and education[edit]
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.[2] 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 personality. He was a correspondent of the Paris Academy of Science and also became a Fellow of the Royal Society. Le Sage died at the age of 79 in Geneva.
Telegraph[edit]
In 1774 he realised an early electric telegraph. The telegraph had a separate wire for each of the 26 letters of the alphabet and its range was only between two rooms of his home.[4]
Kinetic Theory[edit]
Le Sage also tried to explain the nature of gases. This attempt was appreciated by Rudolf Clausius[5] and James Clerk Maxwell.[6] Maxwell wrote: "His theory of impact is faulty, but his explanation of the expansive force of gases" [i.e., pressure] "is essentially the same as in the dynamical theory, as it now stands." Le Sage also clearly pointed out, that he was not the first one who described such a mechanism, and referred to Lucretius, Gassendi, Hermann and Bernoulli.
Gravitation[edit]
History[edit]
In his early youth Le Sage was strongly influenced by the writings of the Roman poet Lucretius and incorporated some of Lucretius' ideas into a mechanical explanation of gravitation, which he subsequently worked on and defended throughout his life. Le Sage wrote in one of his cards, that he developed the basic features of the theory, which was later called Le Sage's theory of gravitation, already in 1743. Then on 15 January 1747 Le Sage wrote to his father:
