BAS'TION. A tower or projecting portion of the walls of a fortification, and the most im portant part of the fortifications of the eneiente. (q.v.) The rampart forming a bastion is con structed as if on four sides of a pentagon, two of which (called the faces) form an angle, with the point toward the exterior; the other two sides (the flanks) connect the extremities of the faces with the adjacent curtains. The fifth (sup posed) side of the bastion is left open, the inter vening space being known as the gorge. The bastion system dates back to the first rude means used. in fortification, which probably consisted of nothing more than simple inclosures, sur rounded with palisades; a devise still em ployed by the natives of semi-civilized States. High walls with breastwork or parapets un doubtedly followed, to enable the defenders to examine the surrounding country. The bastion as it is known to-day, however, is of Italian origin, the most ancient at present existing bear ing the date of 1527, and being situated at Verona. Vauban (q.v.) developed the bastion in his scheme of fortification, and built many famous examples. So far as the use of bastions in the defense of modern forts is concerned, modern armaments may be said to have made them unnecessary; but as it will in all proba bility be a long time before they disappear entirely, the history of fortification is unintelligi ble without some knowledge of them. Every fort
or redoubt, if not circular, must have several sides, which are known as fronts. To enable the defense to concentrate the fire of a whole front on any point opposite it, or to command its own ditches, the line of front is broken up into a number of lines in a peculiar manner, and the result is then said to be a bastioned front. There is no complete bastion in any bastioned front; only two half bastions. If another bastioned front, adjoining this one, were constructed, a complete bastion would appear; and if all the exterior sides inclosing the position were so treated, a complete bastion would appear at each corner. Bastions are generally designated by numbers, as are also the guns and the fronts. The numbers are according to the fronts, and begin with the first one to the right of the exit of the main gate, and continue with the sun. The advantage thus afforded, is that it enables any particular gun to be specified. even if its number be unknown. Thus, the first gun on the right face of the second bastion, etc. See FORTIFICATION.
The relation which bastions bear to the general system of attack and defense is noticed under FORTIFICATION, where is given the historical de velopment of methods of defense, illustrations, and a list of works treating this subject.