The two brothers worked together on a number of projects including an innovative hydraulic engine, the Pyréolophore the world's first internal combustion engine, as well as pioneering work in photography.
Most engine designs that pre-dated the Otto engine (and Clerk engine), such as those of de Rivaz, the Niépce brothers, Jean Joseph Etienne Lenoir, Samuel Morey, and others, did use two stroke engines, which were "natural" in the times of steam engine.