Portee

de but en blanc, Fr. the forward direction and flight of a ball, constituting a straight line, which it describes from the mouth of the piece to its ultimate object. It has been generally found, by experience that the distance so described, could not exceed 300 toises. Beyond that, the ball has been known to deviate. According to Belidor, pieces of ordnance will carry farther in the morning and at night, when the weather is cool and rarefied, than in the middle of the day, or at noon, when the heat of the sun prevails. This circumstance is amply discu ed in his Bombardier Franco is; and his observations were proved to be correct by experiments made in June, 1744, at E onne. These experiments commenced at seven o’clock in the morning, and lasted till twelve. It was remarked, that the shells, which were thrown out of three mortars, gradually fell short of their original range. Besides the portée a toute volée, and the portée de but en blanc, or the full range and the point blank shot, there is the ricochet, which marshal Vauban invented. See Ricochet.