Coulomb, Charles Augustin de (1736-1806), a French physicist and engineer. He is best known for his work in electricity and magnetism. He became interested in scientific research after working out engineering problems in friction and torsion. The unit of electric charge, the coulomb, was named for him.
In 1777 Coulomb invented the torsion balance. (The invention of the torsion balance by John Michell, an English scientist, was made independently.) With this device, Coulomb measured the forces of attraction and repulsion between electrically charged bodies and between the poles of magnets. Using these measurements, Coulomb derived the mathematical formulas (Coulomb's Law of Electrostatics and Coulomb's Law of Magnetostatics) that describe those forces. (Coulomb's Law of Electrostatics is often simply called Coulomb's Law.) Coulomb observed from his measurements that the strength of the forces between electric charges or magnetic poles is inversely proportional to the square of the distance between the charges or the poles. This observation was fundamental to the development of the study of electricity and magnetism.
As a young man, Coulomb served as a military engineer in the West Indies, where he supervised the building of forts. After returning to France in 1772, he began his research in physics.