BORDA, JEAN CHARLES (1733-1799), French mathe matician and nautical astronomer, was born at Dax. Entering the army at an early age he transferred later to the navy, and in 1782 was taken prisoner at sea by the English, but was immediately released on parole. He contributed a long series of valuable memoirs to the Academy of Sciences. His researches in hydro dynamics were highly useful for marine engineering, while the reflecting and repeating circles, as improved by him, were of great service in nautical astronomy. He was associated with J. B. J. Delambre and P. F. A. Mechain in the attempt to determine an arc of the meridian, and the greater number of the instruments employed in the task were invented by him.
See J. B. Biot, "Notice sur Borda" in the Mem. de l'Acad. des Sciences, iv.