One of his first productions was an extremely small quarter repetition watch, placed in a ring, which earned him the recognition of George III. It had a cylinder escapement using a ruby cylinder, the first in this material.

Development of chronometry:

• Made improvements to the bi-metallic compensating balance wheel (patents filed in 1775 and 1782).

• Invented the cylindrical spiral with terminal curves (patents filed in 1782).

• Invention of a spring escapement (patented in 1782). Concomitant invention but probably obtained independently from Thomas Earnshaw and Ferdinand Berthoud.

Rencontre avec A.L. Breguet à qui il donne carte blanche pour se servir de ses inventions.