As to closed contours, they may outline a depression or a hill.

On the map, "881" or "885" might be hills or ponds, as far as their shape is concerned. But, clearly, they are hills, for on either side are small streams running _away_ from them. If they were ponds, the stream lines would run _toward_ the closed contours. The rest of "hill, valley, hill," will always solve the problem when there are not enough stream lines shown to make evident at once whether a closed contour marks a pond or a hill. Look in the beginning for the stream lines and valleys, and, by contrast, if for no other reason, the hills and ridges at once loom up.

To ill.u.s.trate the subject of contours to aid those who have difficulty in reading contoured maps the following is suggested:

1. Secure modeling clay and build a mound.

2. Use wire and slice this mound horizontally at equal vertical intervals into zones; then insert vertical dowels through the mound of clay.

3. Remove the top zone, place on paper, and draw outline of the bottom edge. Trim your paper roughly to the outline drawn. Indicate where the holes made by the dowels pierce the paper.

4. Do the above with each zone of your mound.

5. Place these papers in proper order on dowels similarly placed to ones in original mound at, say, 1 inch vertical interval apart.

A skeleton mound results.

6. Replace the zones of the clay mound and form the original clay mound along the side of skeleton mound.

7. New force all the paper sheets down the dowels onto the bottom sheet, and we have a map of clay mound with contours.

NOTE.--One-inch or 2-inch planks can be made into any desired form by the use of dowels and similar procedure followed.

People frequently ask, "What should I see when I read a map?"

and the answer is given, "The ground as it is." This is not true any more than it is true that the words, "The valley of the Meuse,"

bring to your mind vine-clad hills, a n.o.ble river, and green fields where cattle graze. Nor can any picture ever put into your thought what the Grand Canyon really is. What printed word or painted picture can not do, a map will not. A map says to you, "Here stands a hill," "Here is a valley," "This stream runs so,"

and gives you a good many facts in regard to them. But you do not have to "see" anything, any more than you have to visualize Liege in order to learn the facts of its geography. A map sets forth cold facts in an alphabet all its own, but an easy alphabet, and one that tells with a few curving lines more than many thousand words could tell.

SECTION 2. SKETCHING.

Noncommissioned officers and selected privates should be able to make simple route sketches. This is particularly useful in patrolling as thereby a patrol leader is able to give his commander a good idea of the country his patrol has traversed. Sketches should be made on a certain scale, which should be indicated on the sketch, such as 3 inches on the sketch equals 1 mile on the ground. The north should be indicated on the sketch by means of an arrow pointing in that direction. Any piece of paper may be used to make the sketch on. The back of the field-message blank is ruled and prepared for this purpose. The abbreviations and conventional signs shown on the following pages should be used in making such simple sketches.

Field Maps and Sketches.

The following abbreviations and signs are authorized for use on field maps and sketches. For more elaborate map work the authorized conventional signs as given in the manual of "Conventional Signs, United States Army Maps," are used.

Abbreviations other than those given should not be used.

ABBREVIATIONS.

A. Arroyo. L. S. S. Life-Saving Station.

abut. Abutment. L. H. Lighthouse Ar. Arch. Long. Longitude.

b. Brick. Mt. Mountain.

B. S. Blacksmith Shop. Mts. Mountains.

bot. Bottom. N. North.

Br. Branch. n. f. Not fordable.

br. Bridge. P. Pier.

C. Cape. pk. Plank.

cem. Cemetery. P. O. Post Office con. Concrete. Pt. Point.

cov. Covered. q.p Queen-post Cr. Creek. R. River.

d. Deep. R. H. Roundhouse.

cul. Culvert. R. R. Railroad.

D. S. Drug Store. S. South.

E. East. s. Steel.

Est. Estuary. S. H. Schoolhouse.

f. Fordable. S. M. Sawmill.

Ft. Fort. Sta. Station.

G. S General Store. st. Stone.

gir. Girder. str. Stream.

G. M. Gristmill. T. G. Tollgate.

I. Iron. Tres. Trestle.

I. Island. tr. Truss.

Jc. Junction. W. T. Water Tank.

k.p. King-post. W. W. Water Works.

L. Lake. W. West.

Lat. Lat.i.tude. w. Wood.

Ldg. Landing. wd. Wide.

[Ill.u.s.tration: SIGNS--FIELD MAPS AND SKETCHES]

[Ill.u.s.tration]

MESSAGE BLANKS

[Ill.u.s.tration]

The heading "From" is filled in with the _name_ of the detachment sending the information: as "Officer's Patrol, 7th Cav." Messages sent on the same day from the same source to the same person are numbered consecutively. The address is written briefly, thus: "Commanding officer, Outpost, 1st Brigade," In the signature the writer's surname only and rank are given.

This blank is four and a half by six and three quarters-inches, including the margin on the left for binding. The back is ruled in squares, the side of each square representing 100 yards on a scale of 3 inches to one mile, for use in making simple sketches explanatory of the message. It is issued by the Signal Corps in blocks of forty with duplicating sheets. The regulation envelope is three by five and one-fourth inches and is printed as follows:

UNITED STATES ARMY FIELD MESSAGE.

_To_ . . . . . . . . . . . . . . . . . . . . ._No_ . . . .

(For signal operator only.) _When_sent_ . . . . . . . . . . . . . . . . ._No_ . . . .

_Rate_of_speed_ . . . . . . . . . . . . . . . . . . . . .

_Name_of_messenger_ . . . . . . . . . . . . . . . . . . .

_When_and_by_whom_rec'd_ . . . . . . . . . . . . . . . . .

This Envelope will be Returned to Bearer.

[Ill.u.s.tration]

CHAPTER XII.

SIGNALS AND CODES.