born June 10, 1832, Holzhausen, Nassau died Jan. 26, 1891, Cologne, Ger. German engineer who developed the four-stroke internal-combustion engine. He built his first gasoline-powered engine in 1861, and in 1876 he built an internal-combustion engine using the four-stroke cycle (four strokes of the piston for each explosion), which offered the first practical alternative to the steam engine as a power source. Though the four-stroke cycle was patented in 1862 by Alphonse Beau de Rochas (1815-93), it is commonly known as the Otto cycle since Otto was the first to build such an engine
born Jan. 30, 1902, Leipzig, Ger. died Aug. 18, 1983, London, Eng. German-born British art historian. He studied at various German universities and taught at Göttingen University (1929-33) before moving to England to escape Nazism. There he taught at the Universities of London, Oxford, and Cambridge. He is best known for his writings on architecture, especially his 46-volume series of county-by-county guides, The Buildings of England (1951-74), one of the great achievements of 20th-century art scholarship. He conceived and edited the Pelican History of Art series (1953- ); many of these individual volumes have become classics