Napoleon granted a patent for the Pyréolophore to Nicéphore Niépce and his brother Claude.
Nicéphore Niépce had fled France during the Revolution as he was the son of a wealthy lawyer who was suspected of having royalist sympathies. He later returned to France where he served in Napoleon’s army before resigning on health grounds and becoming the Administrator of the district of Nice.
By 1801 Niépce and his older brother Claude had returned to manage the family’s estate while conducting scientific research. It was here that they developed their internal combustion engine, which harnessed the power of hot air expanding during an explosion. Their first fuel was lycopodium powder, made of dried plant spores, which was ignited inside the airtight copper machine.
The brothers presented their internal combustion engine in a paper to the French National Commission of the Academy of Science in 1806. However, the engine’s major test came in 1807 when it was installed on a boat on the river Saône. Small amounts of fuel were released into a jet of air provided by mechanical bellows inside the machine. The pressure of the explosion forced water out of an exhaust pipe protruding from the boat’s rear. This in turn propelled the boat forward in short bursts, and successfully moved it upstream against the flow of the river.
Following the successful boat test, Napoleon granted a patent to the brothers. However, despite experiments with other fuel sources, they struggled to find a commercial use for their invention. Nicéphore instead turned his attention to photography, and became the first person to produce a permanent photographic image.