Antoine-Laurent Lavoisier was an 18th-century French scientist who is perhaps best known for his role in the discovery of oxygen. Born the son of a lawyer in 1743, Lavoisier studied law himself and became a successful lawyer and public servant in the time of Louis XVI. Throughout his life, however, he pursued scientific inquiry as a hobby.
Most of Lavoisier's early work was in geology, and he was appointed to the French Academy of Sciences in 1769 at the age of 25. During this time, he worked as a tax farmer, collecting taxes for his own profit under a license granted by the king, and married the then 13-year-old Marie-Anne Pierrette Paulze.
Working on the formula for gunpowder, Lavoisier developed recipes and granulation methods that improved the powder's energy release during combustion. He also worked out the weights of the gunpowder's reagents and products in an effort to demonstrate that the mass of the elements would be preserved throughout the chemical reaction process.
It was Lavoisier who coined the word "oxygen" to describe the "dephlogistated air" that Joseph Priestly had isolated in his laboratory in England. During the French Revolution, Lavoisier took a leading role in many reforms, including the adoption of the metric system, but ran afoul of the revolutionary government. He was executed by guillotine in 1794.