Layer Maps

LAYER MAPS Carl Ritter, in 18°6, employed graduated tints, decreasing in depth, from the lowlands to the highlands; while Gen. F. von Hauslab, director of the Austrian Surveys, in 1842, advised that the darkest tints should be allotted to the highlands, so as not to obscure details in the densely peopled plains. C. von Sonklar, in his map of the Hohe Tauern coloured plains and valleys green; mountain slopes in five shades of brown; glaciers blue or white. E. G. Ravenstein's map of Ben Nevis (1887) first employed the spectrum colours, viz., green to brown, in ascending order for the land : blue, indigo and violet for the sea. On the international map of the world, on a scale of 1 :i,000,000, which has been undertaken by the leading governments of the world, the ground is shown by contours at intervals of mom., the strata are in graded tints, viz., blue for the sea, green for lowlands up to 3oom., yel low between 30o and 5oom., brown up to 2,000m., and reddish tints beyond that height.

Until the 20th century the declivities of the ground were indi cated in most topographical maps by a system of strokes or hachures, first devised by L. Chr. Muller (Plan and Kartenzeich nen, 1788) and J. G. Lehmann, who directed a survey of Saxony, 1780-1806, and published his Theorie der Bergzeichnung in By this method the slopes are indicated by strokes or hachures crossing the contour lines at right angles, in the direction of flowing water, and varying in thickness according to the degree of de clivity they represent. Typical modern topographical maps, on scales from 1 :25,000 to i :250,00o, have, generally, contours closely spaced, printed in colours. Hachures may occasionally be found combined with contours, as in the maps of Italy on the i : ioo,000 scale.

As to the interval at which the contours should be spaced, a good rule in normal, not mountainous, country is to space them at 5oft. for a scale of sin. to the mile, and for other scales in

proportion. Thus, on a sin. map the contours would be at iooft. intervals and so on.

Selection of Names and Orthography.

The nomenclature or "lettering" of maps is a subject deserving special attention. Not only should the names be carefully selected with special reference to the objects which the map is intended to serve, and to prevent overcrowding, but they should also be arranged in such a manner as to be read easily by a person consulting the map. It is an accepted rule now that the spelling of names in countries using the Roman alphabet should be retained, with such exceptions as have been familiarized by long usage. In such cases, however, the correct native form should be added within brackets, as Flor ence (Firenze), Leghorn (Livorno), Prague (Praha) and so on. At the same time these corrupted forms should be eliminated as far as possible. Names in languages not using the Roman alphabet, or having no written alphabet, should be spelt phonetically, as pronounced on the spot. An elaborate universal alphabet, abound ing in diacritical marks, has been devised for the purpose by Prof. Lepsius, and various other systems have been adopted for oriental languages, and by certain missionary societies, adapted to the languages in which they teach. The simple rules laid down by the Royal Geographical Society, will be found sufficient.

The United States Geographic Board acts upon rules practically identical with those indicated, and compiles official lists of place names, the use of which is binding upon Government departments.