Gerrit Moll (1785-1838), Dutch physicist. Moll was born in Amsterdam and was apprenticed to a merchant. He spent his spare time studying mathematics and astronomy, and was sent to the Amsterdam Athanaeum by his father to avoid conscription by the French. In 1815 he was made professor of physics at Utrecht. He made measurements of the speed of sound using artillery pieces, made studies of the connection between electricity and magnetism and studied the variation of water density with temperature. He was instrumental in keeping Dutch society in touch with the latest scientific discoveries, a duty he saw as halting the decline of Dutch science.