Jean Léonard Marie Poiseuille

Jean Léonard Marie Poiseuille (22 April 1797 – 26 December 1869) was a French physicist and physiologist.

Life Poiseuille was born in and died in Paris. In 1828, he earned his D.Sc. degree with a dissertation entitled Recherches sur la force du coeur aortique (The force of the aortic heart). He was interested in the flow of human blood in narrow tubes, and invented the U-tube mercury manometer (or hemodynamometer) to measure arterial blood pressures in horses and dogs.

In 1838, he experimentally derived, and in 1840 and 1846 formulated and published, Poiseuille's law (now commonly known as the Hagen–Poiseuille equation, crediting Gotthilf Hagen as well), which applies to laminar flow, that is, non-turbulent flow of liquids through pipes of uniform section, such as blood flow in capillaries and veins. The poise, the unit of viscosity in the CGS system, was named after him; a proposed SI unit for viscosity, the poiseuille, was also named in his honour.