The Pyréolophore (French: [piʁeɔlɔfɔʁ]) was an early internal combustion engine and the first made to power a boat. It was invented in the early 19th century in Chalon-sur-Saône, France, by the Niépce brothers: Nicéphore (who went on to invent photography) and Claude. In 1807 the brothers ran a prototype internal combustion engine, and on 20 July 1807 a patent was granted by Napoleon Bonaparte after it had successfully powered a boat upstream on the river Saône.
The Pyréolophore ran on what were believed to be "controlled dust explosions" of various experimental fuels. The fuels included mixtures of lycopodium powder (the spores of Lycopodium, or clubmoss), finely crushed coal dust, and resin.