Joseph-Louis Proust was a French chemist.
, 1826 in Angers, France
Claim to Fame:
Proust was a French chemist who proved that the relative quantities of the elements that make up a chemical compound is constant, regardless of the component's source. This is referred to as Proust's law or the law of definite proportions. His later work involved the study of sugars. He showed the sugar in grapes is identical to the sugar in honey.