who collected taxes for the government in Paris. In the 1770s he discovered oxygen and nitrogen in air and demolished the phlogiston theory of combustion by demonstrating the role of oxygen in the process. In 1783 he made water by burning hydrogen in oxygen (see Cavendish, Henry). He also devised a rational nomenclature for chemical compounds. In 1794 he was tried by the Jacobins as an opponent of the Revolution (because of his tax-gathering), found guilty, and guillotined.