PLAN OF THE MAP. 9 



poses. The following table presents the scales of the general topographic 

 maps of various European countries: 



Scales of topographic maps of European nations. 



India 1 : 63360 



Great Britain and Ireland 1:63360 



Germany 1:100000 



Austria-Hungary 1 : 75000 



France 1:80000 



( 1:25000 

 Switzerland < 



I 1:50000 



Holland 1 : 25000 



Spain 1:50000 



Italy 1 : 100000 



Sweden 1 : 100000 



Russia 1:126000 



( 1:20000 

 Belgium { 



I 1:40000 



Denmark 1:40000 



Norway 1:100000 



Portugal 1 : 100000 



CONTOUR INTERVAL. 



The relief of the earth's surface is now represented upon maps almost 

 entirely by contour lines or lines of equal elevation. Until a comparatively 

 recent date this element, secondary in importance only to the horizontal 

 element, <>r the plan, has been ignored. 



The contour intervals which have been adopted for the map of the 

 United States are as follows: 



For the scale of 1 : 62500, the intervals range from 5 to 50 feet; for the 

 scale of 1:125000, 10 to 100 feet, and, for the scale of 1:250000, the interval 

 is 200 or 250 feet. 



FEATURES REPRESENTED. 



In this matter, the experience of European nations tends in the direc- 

 tion of reducing the number of features which should be placed upon the 

 map. It has been decided, in the preparation of the map of the United 

 States, to go even beyond the present practice of European nations in this 

 regard and to limit the map to the representation of all natural features 



