Charles Cagniard de Latour

Charles Cagniard de la Tour (1777-1859) was a French physicist and chemist that carried a detailed study of the phase transformation of a saturated liquid under the influence of pressure and temperature and proved that inside a sealed glass tube the fluid would become first a saturated vapor, and then turn continuously into superheated vapor, no matter what the pressure. He discovered the existence of a critical point, without using this concept. Cagniard de la Tour used a microscope to investigate the phenomenon of fermentation, particularly by beer yeast, its causes, and effects, and proved that it was caused by a living organism and was not a pure chemical reaction. He also studied the pyrolysis of woody matter in a sealed atmosphere and showed that it resulted in the formation of tarry and sticky carbonaceous material, accompanied by a gas atmosphere.