Avogadro, Amedeo

19th Century
Born: Turin (Italy), 1776 
Died: Turin (Italy), 1856
Avogadro studied law (1796) before turning to science. He became professor of physics at the University of Turin. In 1811 he proposed his famous hypothesis that all gases (at a given temperature) contain the same number of particles per unit volume. He specified that particles needed not to be individual atoms, but might be combinations of atoms (molecules). He was the first to distinguish between atoms and molecules in this way.