1663-1705

French physicist who conducted the first serious research on air thermometers, showing experimentally that the pressure of a constant mass of air is directly proportional to temperature increases, and deducing from Mariotte's law that any volume of air expands by the same fraction for given temperature changes (1699). Deaf from an early age, Amontons established that friction is proportional to load, designed many instruments including a hygrometer (1687) and conical barometer (1695), and proposed water's boiling point as a thermometric fixed-point (1702).