It was in Nice that Claude and Nicéphore Niépce started their first works as inventors. Their interest was first focused on creating a new engine principle based on the use of air dilatation during an explosion. Did they have any knowledge of the works of Huygens (1625-1695), who had already used air dilated by the explosion of gunpowder in a cylinder to move a piston?

At first, the Niépce brothers used as an explosive a powder made with the spores of a plant: the Lycopodium (broad moss), then they used coal mixed with resin. So they invented the first internal combustion engine, which they named Pyreolophore (pyr=fire, eolo=wind and phore=I carry or I produce).

The 1806 report on the invention of the pyreolophore

In 1806, they wrote a first report. A commission of the National Institute, also known as the Sciences Academy, which had been given the task of evaluating the invention, gave its verdict as follows:

“The fuel ordinarily used by M.M. Niépce is made of lycopodium spores, the combustion of which being the most intense and the easiest one; however, this material being costly, they replaced it with pulverized coal and mixed it if necessary with a small portion of resin, which works very well, as was proved by many experiments. In M.M. Niépces’ machine no portion of heat is dispersed in advance; the moving force is an instantaneous result, and all the fuel effect is used to produce the dilatation that causes the moving force.

In another experiment, the machine installed on a boat with a prow about two feet wide by three feet high, reduced in the underwater part and weighing about 2,000 pounds, went up the Saone river with just the engine power, with a speed greater than the river’s in the opposite direction; the amount of fuel burnt was around one hundred and twenty-five grains per minute, and the number of pulsations was twelve to thirteen in the same amount of time. The Commissioners then conclude that the machine proposed under the name Pyreolophore by M.M. Niépce is ingenious, that it may become very interesting by its physical and economical results, and deserves the approbation of the Commission.”

Report by Lazare Carnot and C.L. Berthollet on December 15th, 1806.

The Niépce brothers had carried out some tests on the lake of Batterey, located in the midst of La Charmée woods, by Saint-Loup-de-Varennes. They obtained a patent for a ten-year duration. This patent was signed by the Emperor Napoléon and is dated July 20th, 1807.

Nicéphore and Claude kept improving the Pyreolophore. On 24th December 1807, they informed Lazare Carnot that they had obtained a highly flammable powder by mixing one part of resin with nine parts of coal. But in 1816 their progress was not sufficient to obtain some subsidies from their invention. The patent’s end was near and Claude decided to go to Paris and then to England, hoping to exploit the engine.