Ernest de Jonquières

Ernest Jean Philippe Fauque de Jonquières (* July 3, 1820 in Carpentras, † August 12 1901 in Mousans -Sartoux in Grasse ) was a French mathematician and naval officer.

Jonquières attended the Naval Academy in Brest and was afterwards in the French Navy. In 1841 he became a lieutenant, and from 1849 to 1850 he served in the Naval Staff in Paris. During this time he became a close associate of Michel Chasles, whose works he had studied. Also during his later years at sea, he continued his mathematical studies and won in 1862 a portion of the Grand Prize of the French Academy of Sciences. In 1865 he became captain and was sent to Saigon to organize a French agricultural and industrial exhibition. He played an important role in the development as a French colony. Later he was Chief of Naval depots and the Department maps and plans. In 1874 he became vice- admiral, and in 1885 he went into retirement.

In 1884 he was elected to the French Academy of Sciences.

As a mathematician, he worked on geometry, based on the works of Chasles and Jean -Victor Poncelet. He dealt with the geometry of algebraic curves and surfaces and abzählender geometry. Later he also studied number theory and the theory of polyhedra, where he discovered that the Euler characteristic was already to be found in Descartes Leonard Euler. In 1859, he led (in Cremona 1863), a special form of Cremona transformation.

Writings

• Mélanges de géométrie pure, 1856
• Notice sur la carrière maritime administrative et scientifique du Vice - Admiral de Jonquières, Paris 1883 ( autobiography)