Pierre René Jean Baptiste Henri Brocard was a French scientist, who is now known chiefly for his work in the geometry of the triangle, but he is also remembered as a French army officer and a meteorologist. In addition, he published several notable papers on mathematics and meteorology.
Background
Pierre René Jean Baptiste Henri Brocard was born on May 12, 1845, in Vignot (a part of Commercy), Meuse, the son of Jean Sebastien Brocard and Elizabeth Auguste Liouville. No record has been found of brothers, sisters, or other close relatives.
Education
Brocard received his early education at the lycée of Marseilles, and the lycée and Academy of Strasbourg. He also attended the École Polytechnique from 1865 to 1867.
After education, Henri Brocard joined the Corps of Engineers of the French army. It is known that he was a prisoner of war at Sedan in 1870, but for the most part, his army career was devoted to teaching and research rather than to active combat. For several years after 1874, he was assigned to service in North Africa, chiefly in Algiers and Oran. He was a co-founder of the Meteorological Institute at Algiers.
As a member of the local committee for the tenth session of the Association Française pour l’Avancement des Sciences, which met in Algiers in 1881, he presented a paper entitled "Étude d’un nouveau cercle du plan du triangle," his first paper on the Brocard points, the Brocard triangle, and the Brocard circle. In 1884 he returned to Montpellier, where he had taught for a short time after his graduation from the École Polytechnique.
There followed appointments to many government commissions and many scientific honors. Brocard served with the Meteorological Commission at Montpellier, Grenoble, and Bar-le-Duc. In 1894 he became a member of the Society of Letters, Sciences, and Arts of Bar-le-Duc; and it is through the publications of this society that one can follow the activities of the last twenty-six years of his life. His scientific and mathematical publications began when he was about twenty-three, and over the years showed him to be an indefatigable correspondent with the editors of mathematical and scientific journals. Brocard contributed to Nouvelles annales de mathématiques, Bulletin de la Société mathématique de France, Mathesis, Zeitschrift für mathematischen und naturwissenschaftlichen Unterricht, Educational Times, El progreso matemático, L’intermédiaire des mathématiciens, and many others. In his autobiography, a brief descriptive paragraph of about three or four lines is devoted to each journal, giving the names of the editors, the dates of publication, etc. These paragraphs provide a succinct and handy source of information, particularly for journals that later ceased publication.
Brocard’s most extensive publication was a large, two-part work entitled Notes de bibliographie des courbes géométriques, followed by Courbes géométriques remarquables, which appeared under the joint authorship of Brocard and T. Lemoyne. The first part of the earlier work appeared in 1897, and the second in 1899. Probably no more than about fifty copies of this work were prepared, lithographed in the printscript of the author, and privately distributed. The Notes may be regarded as a sourcebook of geometric curves, with a painstakingly prepared index containing more than a thousand named curves. The text consists of brief descriptive paragraphs, with diagrams and equations of these curves. About twenty years later, Volume I of the projected three-volume work Courbes géométriques remarquables was published in Paris. In 1967 both Volume II and a new edition of Volume I were published in Paris. Courbes géométriques remarquables is described as an outgrowth of Notes de bibliographie des courbes géométriques.
During the latter part of his life, Brocard made his home in Bar-le-Duc. He lived completely alone and rarely had visitors. He obviously enjoyed his membership in, and his work as librarian of, the Society of Letters, Sciences, and Arts of Bar-le-Duc, although he had declined the honor of becoming president. Largely through his efforts, one of the streets of Bar-le-Duc was named for Louis Joblot, a native Barisian who was an acknowledged but almost forgotten pioneer in the field of microscopy. Brocard honorably retired from the French military in 1910 as a lieutenant colonel. In his retirement, he spent much of his time making astronomical observations with a small telescope in the garden behind his house. Every fourth year he took a long trip to the meetings of the International Congress of Mathematicians.