ns in common use. A key to them is published by the War
Department, and is called "Conventional Signs, United States
Army." From these you read at once the natural and artificial
features of the country shown on your map. It should be borne in
mind that these conventional signs are not necessarily drawn to
scale, as are the distances. They show the position and outline
of the features rather than the size. This, for the reason that
many of the features shown, if drawn to scale, would be so small
that one could not make them out except with a magnifying glass.
If the exact dimensions are of any importance, they will be written
in figures on the map. For instances, bridges.

In addition to te above conventional signs, we have CONTOURS
to show the elevations, depressions, slope, and shape of the
ground. Abroad, HACHURES are much used, but they serve only to
indicate elevation, and, as compared to contours, are of little
value. Contours resemble the lines shown in figure 4 (section
1)

Hachures are shown in figure 5 (section 1), and may be found on
any European map. They simply show slopes, and, when carefully
drawn, show steeper slopes by heavier shading and gentler slopes
by the fainter hachures. The crest of the mountain is within
the hachures. (See fig. 5, section 1.)

_Contours_.--A certain student, when asked by his instructor
to define "space," said: "I have it, sir, in my head, but can
not put it into words." The Instructor replied: "I suppose that
under those circumstances, Mr. ----, the definition really would
not help much." And so it is with contours--the definition does
not help much if you know a contour when you meet it on a map. For
examples of contours, turn to the map in section 2 and, starting
at the United States penitentiary, note the smooth, flowing,
irregular curved lines marked 880, 860, 840, 840, 860, etc.

The only other lines on the map that at all resemble contours
are stream lines, like "Corral Creek," but the stream lines are
readily distinguished from contours by the fact that they cross the
contours squarely, while the contours run approximately parallel
to each other. Note the stream line just to the west of South
Merritt Hill.

The contours represent lines on the ground that are horizontal
and whose meanderings follow the surface, just as the edge of
a flood would follow the irregularities of the hills about it.
Those lines that contours stand for are just as level as the
water's e