Otto engine on a farm. 19th-century illustration of a gas engine (lower right) powering machinery on a farm. A series of belts and wheel and a connecting rod transmit the engine's power to the machinery, which includes a mill and threshing machines. Workers are handling crops to be threshed and ground. A gas engine is an internal combustion engine that runs on a gas fuel. The first practical gas engines included those by German engineer Nikolaus Otto (1832-1891) in the 1860s. Artwork from 'Moteurs' (1911) by French civil engineer Max de Nansouty (1854-1913), part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.