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 an area basis. For the purpose of a visual and mental test, the area basis may be used if Idaho and Texas are compared.

Graham Romeyn Taylor on "Satellite Cities" in the Survey

Fig. 174. Map Showing that Factory Workers of Norwood and Oakley (Cincinnati) Live Long Distances from Their Work, Many in the Heart of Cincinnati Rather than in the Suburbs Near the Factories

The use of much heavier lines on the small circles and the figures in them would have improved this chart. Pins or black-ink dots, each representing say 20 workers, would give a good result by using the method of Fig. 198

The method of Fig. 176 is now quite commonly used in Government publications. This scheme for presenting data is not so striking to the eye as that of Fig. 175, but it is more accurate. The scale given with the map permits the number of cattle for any State to be read fairly accurately. The degree of accuracy depends upon the map size selected, and upon the number of dots used to represent any given quantity. The more dots used the greater the accuracy. There is, however, a limit to the number of dots which may be used, or the dots will of necessity be so small in diameter that the quarter circles will be impossible for the eye to distinguish. In Fig. 176 it would not be feasible to use a much smaller circle if the quarter-circles are used.