Dulong, Pierre Louis

Dulong, Pierre Louis 

Born Feb. 12, 1785, in Rouen; died July 19, 1838, in Paris. French physicist and chemist. Member of the Paris Academy of Sciences (1823).

Dulong was a physician by training and a professor of chemistry at the Paris Veterinary School. Beginning in 1820 he was a professor of physics at the Polytechnic School in Paris. He was the first to obtain nitrogen chloride (1811) and hypophosphorous acid (1816). In 1815, almost simultaneously with H. Davy, he proposed the hydrogen theory of acids. In 1819, together with A. Petit, he established the law of specific heat in solids (Dulong and Petit’s law); they also derived a general formula for the cooling rate of substances and invented the cathetometer. Between 1824 and 1830 Dulong, together with D. F. Arago, determined the pressure of saturated steam at different temperatures (up to 224°C).

WORKS

Recherches sur la mesure des temperatures et sur les his de la communication de la chaleur. Paris, 1818. (With A. T. Petit.)