Jean Charles Borda, a French mathematician, born at Dax, May 4, 1733, died in Paris, Feb. 20, 1799.. He served as a young man both in the army and navy, and gave much study to the principles of projectiles and the construction of vessels. Chosen a member of the academy in 1756, he furnished to it several valuable contributions on these subjects. He was employed by the government in 1771 on expeditions to ascertain the value of chronometers in determining longitudes. He was sent on several geographical expeditions, and was one of the commissioners with Delambre and Mechain to determine the arc of a meridian as the basis of the metrical system of measures and weights. A new instrument for measuring the inclination of the magnetic needle was invented by him, and he made important improvements in the reflecting circle for the accurate measurement of angles. He rose to the rank of major general of marines, serving as such in the American war of independence. He wrote several works on mathematics and navigation, and constructed logarithmic tables for the centesimal division of the quadrant.