Robert Waril. Cliiiiatts of tht Umtrcl States. " Ginn & Co., Boston and Nrw York, I'liS.

Average Annual Number of Rainy Days in the United States.

1. While the contour map is best known for its use in uivinn the topography of land, it may

also be used to show preci(>itation. temperatures, and erosion.

2. Since no key for the shadinus was nivin with this map. it is rather ditlicult to read

accurately.

GRAPHIC PRESENTATION

Robert Ward. "Climates of the United States," Ginn St Co.. Boston and New York, 1925.

A. Average Annual Minimum Temperatures in the United States.

1. Because "contour" means "outline," lines may be used to outline the major temperature

sections of the United States.

2. Comparison with a topographic map would reveal no doubt, a relation between the

elevation of the land and the temperature.

if/mcM/

ieh:

The New York Timei, March 19, 1939. SCALE .6

B. Weather Map of the United States at 7:30 p.m. E.S.T. March 18. 1939.

1. The reports on this map arc for exactly the same time; that is, although it was 7:30 p.m.

Eastern standard time, it was several hours earlier by the clock on the Pacific Coast.

2. Compare this method of indicating rain with the method shown in 234A.

CONTOUR MAPS

National Resources Board. "State PlannioK." 1035.

A. Topographic Map of Colorado, Showing Contour Lines af Intervals of 2000 Feet.

The combination of a topographic map and a profile section makes this a valuable map.

MacElwee 8i Crandall. Inc.. N Y C.