(ii) =Justification for Opening Fire.=--For example, justification for opening fire may be illustrated by the following object-lesson, which will also help men to recognize the limit of individual fire, and explain the need for collective fire beyond close range. Figures representing infantry lines in extended order at 2,000, 1,800, 1,600, 1,400, 1,200, 1,000, 800, 600, and 400 yards, may be exposed on Tiers A and B to represent the advance of an enemy in attack. All the figures will be shown against background which harmonizes with their colouring. The difficulty of discerning targets beyond close range will be demonstrated. The difficulty of estimating the range of the figures beyond close range by the difference in their size, even when difficulties due to atmospheric influences and movement are absent, will also be indicated. Finally, a good shot may be told off to fire five rounds at a 1,000 yards figure; five rounds at a 600 yards figure; and five rounds at a 400 yards figure, to illustrate the limit of probable assurance of fire effect from individual fire, and to demonstrate the principle which underlies justification for opening individual fire--namely, that such fire must not be opened unless there is at least probable assurance of effect. (iii) =Choice of Targets.=--The principle underlying the choice of targets in individual firing may be illustrated in the same manner by arranging figures on the Target so as to represent more or less favourable or important targets between which firers may commonly have to choose. For instance, figures representing a line of men in extended order may be arranged so that the intervals between the men in some parts of the line are considerable, while in others they art crowded together, shoulder to shoulder (see footnote, p. 226). Here the thickest part of the line is the more favourable target. Again, targets which are distinctly visible owing to the effect of background are more favourable than those which are rendered indistinct owing to this cause. Targets consisting of men in the standing position are, other conditions being equal, more favourable than those in the kneeling and lying positions, and men in the open are obviously more favourable targets than those partly concealed behind cover, especially if it affords protection from fire. These object-lessons illustrate the principle underlying the choice of targets--namely, to select the target which gives the greatest probable assurance of fire effect, or which in any given situation is the most important. (iv) Object-lessons illustrating other important points may be arranged on the Target by instructors on the same principle as the above examples.