e lines may then be taken
on or near the line of observation, from the extremities of which
additional base lines may be selected, if necessary, and points toward
the enemy's position located by intersection. Details are sketched in
as in position sketching. For obvious reasons, no traversing should be
done along the line of observation.

=1891. Road sketching.= The following are the instruments used in road
sketching:

1. Drawing board or sketching case;

2. Loose ruler;

3. Scale of strides, or paces, if made dismounted; scale of time
trotting or walking, if mounted;

4. Scale of hundreds of yards, at three inches to 1 mile;

5. Scale of M. D.'s;

6. Slope board (if clinometer is not available).

Methods to be used

(1) At station 1, Fig. 10, orient the board as described in par. 1872,
holding the board in the hands, in front of the body of the sketcher,
who faces toward station 2.

[Illustration: Fig. 10]

(2) Important points in the vicinity, such as the railroad bridge, the
stream juncture, hilltops, are sighted for intersections, lines drawn
as shown and the sketcher traverses to station 2.

(3) At station 2 he locates and draws in all details between station 1
and 2, to include about 300 yards on each side of the road.

(4) The traverse is then continued forward as described for 1 and 2.

(5) After some practice of horizontal sketching, as just described,
the sketcher will be able to take up contouring in combination. The
methods are as described in the paragraph on contouring.

(6) When the traverse runs off the paper as at A, Fig. 10, the
following method is followed: Reorient the board so that the road
forward will lie across the long dimensions of the paper; draw a
meridian parallel to the compass needle and assume a point on the new
sheet corresponding to the last point (A) plotted on the first sheet.

(7) On completion of the sketch various sections will be pasted
together, so that all the meridians are parallel.

=1892. Combined sketching.= Let us suppose that we have the rectangle
W, X, Y, Z, Fig. 11, assigned to us to map and that we have been given
four sketching parties, and that the locations and elevations of A and
B have been previously determined by triangulation and are plotted to
scale on our rectangle.

A logical step would be to carefully plot the line a' b', and then the
lines c' c" and c" d.

If the area is densely wooded we run "line of level" by using the
slope b