Amadeo Avogadro.

Avogadro's work was recognized nearly fifty years after he had made his hypothesis. Two years after his death, his colleague showed how the use of Avogadro's number could solve many of the problems in chemistry. This time Avogadro's paper was looked at more carefully over a wider and more distinguished group of scientists, thus his work was finally recognized. Avogadro's work helped other scientists to solve more problems and develop more theories.

Avogadro has based his work on the findings of Joseph Gay-Lussac in 1809. Gay-Lussac had discovered that all the gases when subjected to an equal rise in temperature, expand by the same amount. Avogadro therefore derived his hypothesis. He also made it clear that the gas particles need not be individual atoms but had made a distinction between the atoms of a substance and its molecules.

Avogadro himself was born on June 9, 1776 in Turin, Italy. He began his career in 1796 by obtaining a doctorate in law and practicing as a lawyer for three years after. In 1800, he began to take private lessons in mathematics and physics and decided to make the natural sciences his profession. He was appointed as a demonstrator at the Academy of Turin in 1806 and the Professor of Natural Philosophy at the College of Vercelli in 1809, and in 1820, he was appointed the professor of mathematical physics. Avogadro died on July 9, 1856 in Turin, Italy.