“ Congreve was an ingenious and versatile man of science. Besides the war rocket he invented a gun-recoil mounting, a time-fuze, a parachute attachment to the rocket, a hydropneumatic canal lock and sluice (1813) , a perpetual motion machine (see Perputual Motion) , a process of colour printing (1821) which was widely used in Germany, a new form of steam-engine, and a method of consuming smoke (which was applied at the Royal Laboratory) ; he also took out patents for a clock in which time was measured by a ball rolling on an inclined plane; for protecting buildings against fire ”