He was trained as an architect but worked in his family business of paper industry when his eldest brother died. He made innovations in the paper industry in his family mills thus earning him recognition from the government of France
In 1782, both the brothers discovered that heated air from a fire directed into a fabric bag will make the bag rise in to the sky.
The two brothers for their inventions were thanked by the French Academy des Sciences.
Later, they published books on aeronautics, Joseph invented a calorimeter and the hydraulic ram, and Etienne developed a process for manufacturing vellum.