Johann Heinrich Lambert

Johann Heinrich Lambert (1728 to 1777) was an Alsatian polymath from the Republic of Mulhouse who made fundamental contributions to mathematics, physics, philosophy, astronomy and map projections. Largely self-taught after leaving school at twelve, he joined the Prussian Academy of Sciences in Berlin in 1763 and worked beside Leonhard Euler. In mathematics he gave the first proof that pi is irrational and systematised hyperbolic functions in trigonometry. His theorems on conic sections made the calculation of comet orbits simpler, and his Neues Organon of 1764 set out the rules of syllogistic reasoning. He also treated map projections, invented the first practical hygrometer and wrote on photometry. This entry records him for his work on calculation and formal logic.