Engraving with signature of Sir Francis Pettit Smith (1808-1874), inventor of the screw propeller. The screw propeller had four curved blades, which pushed the water backwards and propelled the boat forward. In contrast to the paddle wheel commonly in use, the screw propeller stayed under water and was thus les easily damaged. In 1839, Smith built the first succesful screw-propelled steamer, the 'Archimedes', which convinced the English Admiralty of their superiority over sailing vesels. Then, in 1843 he built the 'Rattler', the first screw warship for the Royal Navy. In 1860, Smith was appointed curator of the Patent Office Museum, whose collections formed part of the newly created Science Museum in 1870.
© Science Museum / Science & Society Picture Library