Painting, Sir Francis Pettit Smith (1808-1874) / by William Boxall, c.1856. Oil on canvas, portrait, 90x70cm in gilt frame, 121.5x101.5x8.5cm. Portrait, HL.Francis Pettit Smith co-inventor of of screw propeller and driving force behind first screw-propelled steamship. In 1860 he became curatoer of the Ptent Museum in South Kensington. Willaim Boxall (1800-1879) was a portrait painter nd 1866-1874 he was Director of the National Gallery.