(ii) Collective concentrated fire is also used to form a cone of fire for observation of fire, when results can be noted by the dust raised by the strike of bullets on the ground or by the effect of fire upon the enemy. It must be clearly impressed upon the mind of the soldier at this stage that, _however skilful individual men may be as marksmen, the greatest effect is produced by their fire only when it is efficiently directed and controlled_. =2.= (i) The soldier must also be made to understand clearly why effect cannot be obtained from individual fire in battle beyond close range, and why collective fire is necessary for fire effect at all ranges beyond close range. The answer to this question may be stated simply and very broadly as follows: In effect, for various reasons, the individual marksman cannot as a rule see his target clearly or at all with the naked eye beyond close range on service, and he can neither aim at it with accuracy nor be certain of its exact range. Moreover, the effect of inaccurate firing, whether due to excitement, fatigue, or other causes, increases with distance. (ii) Clearly, therefore, the soldier cannot obtain reasonable assurance of fire effect by individual fire beyond close range. Accordingly, fire-unit commanders equipped with field-glasses discern and indicate targets to him. They give him ranges after they have been ascertained by the use of range-finding instruments, or by observation of fire, when possible, and they direct the fire of a number of individual soldiers in a volume which, whether distributed or concentrated, is sufficient to compensate for individual errors, and so obtain fire effect as described in Secs. 12 and 13, and in Chapter VI. =3.= The principal reasons which militate against the assurance of fire effect, by individual fire, beyond close range may be summed up as follows: The effects of fatigue and excitement on the firer; the effects of atmosphere, heat, and light; errors due to imperfections in the rifle and ammunition; uncertainty in estimating longer ranges; the difficulty of discerning and aiming at small, moving, and indistinct or invisible targets; and the steepness of the angle of descent of the bullet, which becomes rapidly accentuated, and so decreases dangerous space as range increases.