Louis Clément François Breguet

[3] and a later step-by-step telegraph system (1847) was applied to French railways and exported to Japan.

He observed in 1847 that small wires could be used to protect telegraph installations from lightning, the ancestor of the fuse.

In 1850 he manufactured a rotating mirror used by Hippolyte Fizeau to measure the relative speed of light in air and water.

He was made a member of the French Academy of Sciences in 1874,[6] and was elevated to Officer of the Legion d'Honneur in 1877.

[8] Breguet was married and had one son Antoine (1851–1882) who also joined the family electrical business.