4. Foreground Range Sketch.—(i)[Fig. 46] shows an example of a foreground range sketch for use in a defensive position. Such a sketch would as a rule only be made in connection with very carefully prepared firing-points; but as from seven to ten hours or more is required to make any serious attempt to prepare and conceal a series of firing-points carefully, it is clear that the range-taking and range-marking party should have ample time to make an exhaustive reconnaissance of the foreground, to put out the range-marks, and to record their work in some simple form. One sketch such as [Fig. 46] is sufficient for the commander of a group of firing-points.
(ii) Points, the range of which may be ascertained and marked with advantage in such sketches, include the exits and entrances to all areas of dead ground, or likely cover from view or fire; the crests or skylines—as seen from the firing-points—of all ridges and humps on the foreground; patches or lengths of road likely to be traversed by the enemy; gaps and gates in fences; corners of fields and enclosures; bridges, culverts, etc.; and conspicuous single objects, as guide-marks from which to estimate adjacent distances, such as isolated buildings, signposts, rocks, milestones, double telegraph-posts, or other such features.
(iii) As will be seen in [Fig. 46], names may also be allotted to patches of dead ground within 1,000 yards or so of the firing-point. The abbreviated names of months and days of the week lend themselves to such a purpose, though any other short names will do equally well.
Fig. 46.—Example of a Foreground Range Sketch.
Note.—Ranged points are indicated by a thick line. The appearance of the Range-Marks is shown thus:—VIII. [= 850 yds.] Names have been allotted to important dead spots within 1,000 yards—e.g., Feb. refers to the dead area immediately behind the ridge ranged as 850.
5. Range-Marks.—Range-marks are of special value to the defenders in those firing-points in which they have been told off to watch for and deal with the enemy’s supports and reserves during their advance, after fire has been opened and the enemy’s firing-line is already pinned down, or is unable to cross certain areas on a foreground prepared for defence until strongly reinforced (see [p. 162], para. 3 (x), Field Entrenchments of this series).
6. Marking Ranges on Ground.—(i) The actual marking of ranges on the ground by means of visible marks may be done as follows: Range-marks should be provided, and should be placed on that side of large trees, houses, banks, etc., which is only visible to the defence. The simplest arrangement consists of one white object per 100 yards range; 500 yards may be denoted by the sign V, made with two boards, poles, etc.; and 1,000 yards by the sign X; intermediate hundreds being indicated by single objects in addition, as above described. On a bank or slope facing the firing-points Roman numerals may be cut out on the turf, etc., or formed by arranging stones or planks.
(ii) Marking on Trees.—For marking on a tree the hundreds marks must be one below the other, and patches of tin do very well for this. For marking “fifties” an object much smaller but distinctly visible may be added, or one object quite different to the remainder. On a tree marked with tin discs, for example, half a disc would do for 50 yards.
(iii) Marking on Buildings.—For marking on a building, the colour to be used depends on that of the masonry, etc. A whitewash-brush is one of the best implements, if obtainable, and the marking, can be either large Roman numerals or ordinary figures if they can be read clearly.