One of the ablest and best-known French makers of scientific instruments of his time. The chemist Antoine-Laurent Lavoisier (1743-1794) particularly appreciated the air pumps presented by Fortin to the Académie Royale des Sciences; he often worked with Fortin on the construction of precision balances, thermometers, and other apparatus. At the end of the eighteenth century, Fortin played a major role in the experimental work that led to the manufacture of metric-system prototypes. He was the favorite instrument-maker of many other leading French scientists, building numerous devices used in physics, chemistry, geodesy, and astronomy. He is also remembered for a type of barometer that bears his name.