(b Sevran, Seine-et-Oise, France, 5 September 1792; d. Paris, France, 20 March 1857)
With Élie de Beaumont and under the direction of Brochant de Villiers, Dufrénoy prepared the first modern geological map of France. He published over sixty memoirs on geology and crystallographic and chemical mineralogy and an important mineralogical work entitled Traité de minéralogie. As the inspector of courses and later director of the École des Mines, he instituted important changes in the curriculum and teaching methods.
Dufrénoy’s father had been Voltaire’s literary agent, and his mother, Adélaïde, was a scholar of the classics and an accomplished poet. Thus the boy grew up in an intellectual atmosphere despite the family’s extreme poverty, occasioned by the French Revolution and the father’s loss of eyesight. Dufrénoy first attended the lycée at Rouen and then the Lycée Louis-le-Grand in Paris. He won the first prize in mathematics at the general examinations in 1810 and entered the École Polytechnique in 1811. In 1813 he was admitted to the École des Mines, at that time located at Peisey in Tarentaise (Savoy), and he returned with it when the school was moved to Paris in 1816. In 1818 he was named engineer of mines and head of the collections at the École des Mines. Stimulated by the publication of Greenough’s geological map of England, Brochant de Villiers was successful in gaining authorization for the preparation of a similar map of France. Dufrénoy and Élie de Beaumont were selected to carry out the necessary fieldwork and in 1822 were sent to England for two years to learn Greenough’s procedures. As a result of this visit, Dufrénoy and Élie de Beaumont coauthored a work entitled Voyage métallurgique en Angleterre, which described in detail the mining and metallurgical industries of England.
For the French geological map Dufrénoy was assigned the area south and west of a line running from Honfleur, Alençon, Avallon, Chalons-sur-Saône, and the Rhone. Each summer from 1825 to 1829 Dufrénoy and Élie de Beaumont made field trips, surveying and taking notes on their respective areas; from 1830 to 1834 they traveled together in order to resolve difficulties and coordinate their work. They published their notes between 1830 and 1838 and the explanation of their map in 1841. The map was on a scale of 1:500,000, and the explanation was essentially a physical description of France, together with the history, composition, and disposition of its terrain. They did not perform any detailed stratigraphic work. The regions of the Pyrenees and Britanny had hardly been explored geologically at that time, and Dufrénoy’s work in these areas was excellent. He was admitted to membership in the Académie des Sciences in 1840, and in 1843 the Geological Society of London presented the Wollaston Medal to Dufrénoy and Élie de Beaumont jointly for their work.
While preparing the geological map, Dufrénoy was also engaged in other important studies. In 1830 he determined that the large coal deposits in the department of Aveyron could be used directly in various metallurgical processes, as the English had been doing; his study resulted in the establishment of industries at Decazeville. In 1832 he was sent to Scotland to study the use of high-temperature air in iron blast furnaces, and his detailed report caused the French iron industry to adopt this practice immediately. He also studied the thermal springs at Vichy and drew up plans for their exploitation.
Dufrénoy served as assistant professor of mineralogy at the École des Mines from 1827 to 1835 and as professor from 1835 to 1848. In 1836 he became inspector of courses there and director of the school in 1846, so that, in effect, he governed instruction in the institution for twenty years, until his death in 1857. During his tenure Dufrénoy introduced to courses the use of specimens from the rich mineralogical collection, and he modernized the curriculum by adding courses in railway construction, law, economics, and paleontology. He entered the Conseil des Mines in 1846 and was promoted to the superior grade in 1851. After Brongniart’s death in 1847, Dufrénoy was named professor of mineralogy at the Muséum d’Histoire Naturelle.
I. Original Works. With Élie de Beaumont, Dufrénoy published the following works: Voyage métallurgique en Angleterre. 2 vols. (Paris, 1827): Mémoires pour servir à une description géologique de la France, 4 vols. (Paris, 1830–1838); and Explication de la carte géologique de la France, rédigée sous la direction de M. Brochant de Villiers, 3 vols. (Paris, 1841). In addition, Dufrénoy published Mémoire sur la position géologique des principales mines de fer de la partie orientale des Pyrénées (Paris, 1834); and Traité de minéralogie, 4 vols. (Paris, 1844–1847). His sixty-five memoirs were published principally in the Journal des mines, the Annales des mines, and the Annales de chimie et de physique.
II. Secondary Works. On Dufrénoy or his work, see A. d’Archiac, Notice sur la vie et les travaux de P. A. Dufrénoy (Paris, 1860); A. Daubrée, “Dufrénoy,” in École polytechnique: Livre du centenaire 1794–1894, I (Paris, 1895), 375–381; and A. Lacroix, “Notice historique sur le troisième fauteuil de la section de minéralogie,” in Académie des sciences—séance publique annuelle du lundi 17 décembre 1928 (Paris, 1928), pp. 24–33.
John G. Burke