_Passive_ DEFENCE is chiefly confined to inundations, and is effected by letting out water in such a manner, that the level ground which lies round a fortified town or place may be entirely overflowed and become an inert stagnant pool. Mere _submersion_ is, in fact, the distinguishing character of this species of defence, which does not afford any other movement than what naturally arises from the greater or lesser elevation of the waters, without the means of urging them beyond a given point. _Distant_ DEFENCE, consists in being able to interrupt the enemy’s movements by circuitous inundations; to inundate, for instance, a bridge, when a convoy is passing, or to insulate batteries, the heads of saps or lodgments which have been made in the covert way is to act upon a distant defence. By this species of defence an enemy’s communications may be perpetually intercepted, and his approaches so obstructed as to force him to leave dangerous intervals. See Belidor’s treatise on Hydraulic Architecture. _Line of_ DEFENCE, represents the flight of a musquet ball from the place where the musqueteers stand, to scour the face of the bastion. It should never exceed the reach of a musquet. It is either fichant or razant: the first is when it is drawn from the angle of the curtain to the flanked angle; the last, when it is drawn from a point in the curtain, razing the face of the bastion. _Line of_ DEFENCE is the distance between the salient angle of the bastion, and the opposite flank; that is, it is the face produced to the flank. See FORTIFICATION. DEFENCE _of rivers_, in military affairs, is a vigorous effort to prevent the enemy from passing; to effect which, a careful and attentive officer will raise redoubts, and if necessary join curtains thereto: he will place them as near the banks as possible, observing to cut a trench through the ground at the windings of the river, which may be favorable to the enemy, and to place advanced redoubts there, to prevent his having any ground fit to form on, &c. See RIVERS. _To be in a posture of_ DEFENCE, is to be prepared to oppose an enemy, whether in regard to redoubts, batteries, or in the open field. _To_ DEFEND, to fortify, secure, or maintain a place or cause. DEFENSE, _Fr._ See _Ligne de_ DEFENSE. DEFENSE, _Fr._ _être en défense_, technically signifies to be in a state of defence, or able to resist. The French usually say: _Cette redoute est en défense_. This redoubt is in a state of defence. DEFENSES _d’une place_, _Fr._ See DEFENCE in FORTIFICATION. DEFENSIVE, serving to defend; in a state or posture of defence. DEFENSIVE-_war_. See WAR. DEFIANCE. See CHALLENGE. DEFICIENT, wanting to complete, as when a regiment, troop, or company has not its prescribed number of men.