Base maps to be used for presenting quantitative data may be secured from the following companies:

American Map Co., New York, N. Y.

Educational Exhibition Co., Providence, R. I.

C. S. Hammond ^^ Co., New York, N. Y.

Rand-McNally Co., New York, Chicago, Washington, D. C, San Francisco, and Los Angeles

Maps may be ordered in many different forms: paper; clothmounted; sized surface; washable surface; wooden rollers; springroller case; pin-map board; cork carpet for pins; framed and braced.

In making graphic representations of different sections of a city, it is often difficult to secure base maps of a suitable scale. Frequently maps can be obtained from the various city departments, or from public utility companies covering the area of special interest.

GENERAL USE OF MAPS

""^JjENERAL information about United States government ^^^m maps may be secured from Map Information Office, North H^H Interior Department Building, Washington, D. C. Aerial photographs are card-indexed, as well as other maps. This enables the Map Information Office generally to state whether or not an area has been photographed, and if so. from what source prints are procurable. The following are important government mapping agencies from which maps may be obtained directly:

Geological Survey, U. S. Department of Interior. Basic topographic maps of approximately one-half the United States. Key

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