iii. Reconnoitring and watching ground in the vicinity of

batteries to assist in ensuring their safety.

iv. Supplementing other means of intercommunication.

These duties cannot all be performed simultaneously with the number of men available. A commander must, therefore, husband his resources so as to have one or more of his headquarters available in an emergency.

4. The training should be individual and progressive and should be made as interesting as possible. The following sections are intended to serve as a guide to the principal points to which attention should be directed.

=241.= _Visual training._

1. The men should be taken to some ground with a good view all round, and each in turn questioned as to what he makes of distant objects such as men, cattle, bushes, rocks, &c.; his answers being checked with field glasses by the instructor. These practices should be repeated till the men are proficient at picking out objects under varying circumstances of light, atmosphere, background and surroundings.

2. The effect which these conditions have on the appearance and apparent distance of objects should be pointed out. Thus the ranges to objects are underestimated in a bright light or clear atmosphere, when background and object are of different colours, with the sun at one’s back, with water or snow to look over and when looking up or down hill.

With a dark background, with the light in the eyes, on broken ground and when looking over a valley or undulating ground, the ranges to objects are overestimated.

Objects dimly seen at evening, and in misty weather, appear more distant and larger than in reality. When the sun shines on entrenchments, the salient parts project their shadows on to the re-entering parts and when freshly raised they look lighter than the surrounding ground.

=242.= _Training in judging distance._

1. The faculty of judging distances correctly can be developed by practice, but rapid and accurate estimates cannot be expected until the visual powers of the soldier have been developed.

When judging distance a man must not be allowed to guess, but must be made to give reasons for his estimate.

2. The following is the system usually recommended:--