Joseph Louis Gay-Lussac
Joseph-Louis Gay-Lussac (1778-1850) was a French chemist and physicist. He is known mostly for two laws related to gases.
In 1802, Gay-Lussac first formulated the law that a gas expands linearly with a fixed pressure and rising temperature (usually better known as Charles's Law).
In Paris a street and a hotel near the Sorbonne are named after him.