Amedeo Avogadro

Amedeo Avogadro (1776-1856) was an Italian chemist and physicist chiefly known for his contribution to molecular theory, now known as Avogadro's law, formulated in 1811. Both the molecular weights and a system of atomic weights are derived by using this law. He is also known for Avogadro's number or Avogadro's constant.