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 Maps on the scheme of Fig. 184 are made entirely in the plane of the paper itself. In Fig. 185 we have a map presentation in which quantities are represented by building vertically above the various routes laid out on the map. For the map of Fig. 185, the vertical representation was made by strips of wood, alternately black and white, glued carefully above each one of the street-car routes. Each of the strips of wood represents 4,000 passengers carried on the street-car lines in 24 hours. The model gives the whole transit situation with surprisingly great clearness, and a better presentation than this could scarcely be imagined.

Railway Age Gazette

Fig. 184. Map Diagram Showing Freight-traffic Density and Direction on the St. Louis and San Francisco Railroad for the Fiscal Year 1912-13

The figures are in terms of 100,000 net tons hauled one mile per mile of road.

A map of this kind is easily made and is often of very great utility. The method can also be used to show the number of passengers carried on railroad, subway, or street-car lines, etc. Compare Fig. 185

The method used in the construction of the model shown in Fig. 185 gives magnificent results, but wooden strips are not practicable except on a very spacious map. The wood-strip method also involves a large amount of time on the part of a skilled workman, and workmen to