=Fire Effect.=--The effect on the target resulting from the fire aimed at it. =Fire Fight.=--The struggle for fire superiority. =Fire Position.=--Positions from which fire is opened during the advance of an attacking force; during the early stages of the advance with a view to gaining ground, in the latter stages with a view to gaining a superiority of fire. =Fire-Unit.=--A unit, the fire of which is controlled by one commander. The normal cavalry and infantry fire-unit is the troop and section respectively. =Firing-Line.=--In extended formations the line of troops from which the main body of fire is delivered. =Firing-Position.=--The position, standing, kneeling, lying, etc., adopted for firing, according to circumstances. =First Catch.=--The first catch is that point where the bullet has descended sufficiently to strike the head of a man, whether mounted, standing, kneeling, lying, etc. (Fig. 4, A). =First Graze.=--The first graze is the point where the bullet, if not interfered with, will first strike the ground (Fig. 4, B). =Group, Grouping, or Diagram of Group.=--The pattern made on a vertical target by a series of shots fired by an individual or the pattern made on a horizontal surface by concentrated collective fire. =Grouping.=--An elementary musketry practice designed to test and standardize holding and the accuracy of rifles, and to expose constant errors in aiming. =Holding.=--The form of skill required in order to press the trigger without disturbing the aim. =Inclined Sights.=--A common fault in aiming-failure to keep the sights upright. =Line of Departure.=--The line of departure is the direction of the bullet on leaving the muzzle--_i.e._, the prolongation of the axis of the barrel (Fig. 2). =Line of Fire.=--The line of fire is a line joining the muzzle of the rifle and the target (Fig. 2). =Line of Sight.=--The line of sight is a straight line passing through the sights and the point aimed at (Fig. 2). =Marking Down.=--Noting the exact position of an enemy seen to occupy ground or cover. =Mutual Support.=--The fire of one unit directed at the enemy to cover and assist the movement of another unit (Fig. 48). Also individual soldiers working in pairs to assist each other in firing. =Observation.=--Watching the effect of fire on the target with a view to correction or verification of sighting, either by watching for the dust thrown up by bullets or the behaviour of the enemy. =Permissible Error.=--Error made in estimating range which does not render fire ineffective. =Ranges, Terms applied to.=