Charles-Augustin de Coulomb was a French physicist best known for the formulation of Coulomb's law, which defines the force between two electrical charges and is, in fact, one of the principal forces in atomic reactions. Performed extensive research on the friction encountered in machinery and windmills, the elasticity of metal and silk fibers, and the description of the electrostatic force of attraction and repulsion. He also did important work on friction. The SI unit of electric charge, the coulomb, was named in his honor in 1880. Charles Augustin de Coulomb was born to Henry Coulomb, an inspector of the royal demesne originally from Montpellier, and Catherine Bajet. The family moved to Paris early in his childhood, and he studied at Collège Mazarin. His studies included philosophy, language and literature. He also received a good education in mathematics, astronomy, chemistry and botany. He graduated in 1761 and joined the French army as an engineer with the rank of lieutenant. Over the next twenty years, he was posted to a variety of locations where he was involved in engineering: structural, fortifications, soil mechanics, as well as other fields of engineering. His health suffered setbacks during the three years he spent in Martinique that would affect him for the rest of his life. On his return to France, Coulomb was sent to Bouchain. He began to write important works on applied mechanics and he presented his first work to the Académie des Sciences in Paris in 1773. In 1779 Coulomb was sent to Rochefort to collaborate with the Marquis de Montalembert in constructing a fort made entirely from wood near Île-d'Aix. Also in 1779 he published an important investigation of the laws of friction, which was followed twenty years later by a memoir on fluid resistance. Upon his return to France, with the rank of captain, he was employed at La Rochelle, the Isle of Aix and Cherbourg. He discovered first an inverse relationship of the force between electric charges and the square of its distance and then the same relationship between magnetic poles. Later these relationships were named after him as Coulomb's law. He was recalled to Paris for a time in order to take part in the new determination of weights and measures, which had been decreed by the Revolutionary government. He became one of the first members of the French National Institute and was appointed inspector of public instruction in 1802. His health was already very feeble and four years later he died in Paris.[3] Coulomb leaves a legacy as a pioneer in the field of geotechnical engineering for his contribution to retaining wall design. His name is one of the 72 names inscribed on the Eiffel Tower.