1161. Hill, B. B. Jan. 16. Maps and charts -A copy of a topographic map is projected by a projecting camera on a large screen and a tracing is made, thus forming a map on a large scale, say from 5 to 30 ft. to the inch. The tracing is painted, or pieces of paper coloured &c. to represent the nature of the country are pasted on the screen, which may be in sections. The screen may be of wood, plain or covered with enamel or linoleum, of concrete, or of asphalt. The screen may be formed of paper mounted on canvas and cloth chemically treated to prevent rotting. The sections are sewn together if of canvas or cloth. Fig. 1 shows a topographic map formed in sections. 5 represents woodland, 12 a fortification, &c. War games are played on the map by manoeuvring figures representing war appliances &c.
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