Johann Andrea von Segner
Born: 9 Oct 1704 in Pressburg, Hungary (now Bratislava,
Slovakia)
Died: 5 Oct 1777 in Halle,
Germany
The Hungarian version of Segner's name is Jan Andrej Segner while in German it is often given as Johann Andrea von Segner.
Segner attended school at Bratislava's Lyceum where he showed special talents for medicine and mathematics. In 1725 he entered the University of Jena, studying medicine there. He did not find being a doctor of medicine to his liking and he returned to the academic world accepting a chair at the University of Jena.
He had the great distinction of becoming the first professor of mathematics at Göttingen taking up the chair in 1735. Segner's was therefore the first to fill what was to become one of the foremost chairs of mathematics in the world. In 1743 Segner was put in charge of the construction of the university observatory which was finished in 1751.
While at Göttingen Segner discovered that every solid body has 3 axes of symmetry. He used Daniel Bernoulli's theoretical work on the 'reaction effect' to produce a horizontal waterwheel using the same principle which drives a modern lawn sprinkler. Segner's work, which influenced Euler to work on turbines, is described in [6]:-
Segner's wheel established the basic principles on which the jet turbine was developed decades later. It works on the principle of a stream of water coming out of a cylinder which at its lowest part has several horizontal paddles bent in one direction. The water streaming through the paddles produces a counter-pressure able to turn the cylinder in the opposite direction.
In 1751 Segner introduced the concept of the surface tension of liquids and made an unsuccessful attempt to give a mathematical description of capillary action.
He left Göttingen in 1755 and, with Euler's assistance, became professor at Halle. Other work which he undertook included the theory of spinning tops. His publications include Elements of Arithmetic and Geometry and Nature of Liquid Surfaces.
Segner received many honours for his work. He was made a member of the Academy of Science in St Petersburg, the Academy in Berlin and the Royal Society in London. Recently he has been honoured with a crater on the Moon being named after him.