Antoine Baum (February 26, 1728 - October 15, 1804), French chemist, was born at Senlis.

He was apprenticed to the chemist Claude Joseph Geoffroy, and in 1752 was admitted a member of the École de Pharmacie, where in the same year he was appointed professor of chemistry. The money he made in a business he carried on in Paris for dealing in chemical products enabled him to retire in 1780 in order to devote himself to applied chemistry, but, ruined in the Revolution, he was obliged to return to a commercial career.

He devised many improvements in technical processes, e.g. for bleaching silk, dyeing, gilding, purifying saltpetre, etc., but he is best known as the inventor of the hydrometer associated with his name (often in this connection improperly spelt "Beaum"). Of the numerous books and papers he wrote the most important is his Elémens de pharmacie théorique et pratique (9 editions, 1762-1818). He became a member of the Academy of Sciences in 1772, and an associate of the Institute in 1796. He died in Paris on the 15th of October 1804.