Antoine Lavoisier (26 August 1743-8 May 1794) was a French chemist who is most famous for having discovered the elements of oxygen, silicon, and hydrogen, discovered the conservation of mass, and that sulfur was an element (not a compound).
Antoine Lavoisier was born in Paris, France on 26 August 1743, the son of a wealthy family as nobles. While he initially studied to become a lawyer and gained his law degree, he devoted himself to science during the 1770s. In 1771, he married his lab assistant Marie-Anne Pierrette Paulze, who translated English works into French so that Lavoisier could further his studies. In 1777, he discovered that sulfur was an element instead of a compound, followed by his discovery of oxygen in 1778, hydrogen in 1783, and silicon in 1787. Lavoisier was also a political activist, calling for insurance and retirement funds for the elderly, the abolition of forced work for peasants, and free trade, and he improved the quality of the French Army's munitions while serving on the Gunpowder Committee after 1775. During the French Revolution, he succeeded in convincing the National Convention to adopt the metric system in 1793, but he was later censured due to political reasons, and he was accused of selling adulterated tobacco by radical pamphleteer Jean-Paul Marat. On 8 May 1794, he was guillotined during the Reign of Terror, and a statue was built in Paris to commemorate him; his name is one of the 72 names inscribed on the Eiffel Tower.