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. Character and health Le Sage described his manner of thinking and working by saying: I have been born with four dispositions well adapted for making progress in science, but with two great defects in the faculties necessary for that purpose. 1. An ardent desire to know the truth; 2. Great activity of mind; 3. An uncommon (justesse) soundness of understanding; 4. A strong desire for precision and distinctness of ideas; 5. An excessive weakness of memory; 6. A great incapacity of continued attention. Le Sage also suffered from insomnia, and as a result of this he often was unable to work for days. Additionally, in 1762 he had an accident which left him nearly blind. To compensate the weakness of his memory, he wrote his thoughts on playing cards – over 35000 cards are still lying in the library of Geneva. As a consequence of his mental disposition, many of his papers remained unfinished and unpublished. For example: his main work on Gravitation; a history of theories of gravitation; a treatise on final causes; a biographical note on Nicolas Fatio de Duillier. However, some of them were posthumously published by his pupil Pierre Prévost. Telegraph 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. Kinetic Theory Le Sage also tried to explain the nature of gases. This attempt was appreciated by Rudolf Clausius and James Clerk Maxwell. 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 History 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