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Science and Citizenship other publications, one must learn the interpretation of the symbolism and notation of the maps, and one must acquire familiarity with the few technical formulæ which occasionally break through the ordinary and simple language of its letterpress. There are simple, easy, and pleasant ways of achieving both these ends—in fact, short-cuts by which one may penetrate right into the heart of geographical science. To master the symbolism and notation of cartography, all one has to do is to compare the best contour maps (that is to say, those of the Ordnance Survey) with what one sees with naked eye, with field-glass, or with telescope, when one ascends the high points of vantage in one's own region. These high points of vantage are, of course, for the towns and cities, their towers, such as they may be; and for the surrounding country, whatever mound, hill-top, or mountain summit one's excursions and explorations may discover. The primary problem of the cartographer is to show by symbolic notation on a flat surface all the varying heights and shapes assumed by, or imposed upon, the earth's surface, above or below sea-level. What the ideal geographer, as cartographer, first of all tries to do is to devise a notation by which he and his fellow-geographers, by the inspection of a map of a given region, may get a simultaneous vision of the terrestrial phenomena which all the explorers and observers of that region have collectively seen. Now it must always be that however minutely observed and explored a region—even the most 37