Perpendicular

( Perpendiculaire, Fr. ) According to Vauban’s system, it is a line raised in a perpendicular direction on the centre of the exterior side of any given polygon. In mean fortification, which prevails more than any other system, the perpendicular contains 30 toises in the exagon, and in polygons that have a greater number of sides; but it contains fewer when the polygons have a le number. The perpendicular is used by this engineer to determine the other lines and angles belonging to a fortification. In proportion as the perpendicular is increased, the extent of the flanks is augmented.