336 



PHYSIOGRAPHV. 



[CH. XIX. 



Mercator's projection, for the poles ar6 supposed, by the 

 cylindrical development, to be indefinitely distant. Such 

 a map is therefore not used in the navigation of arctic seas, 

 but is otherwise universally employed by mariners. 



For arctic charts the po/ar projection represented in Fig. 

 no, is commonly used. Here the parallels of latitude an,- 



Fig. no. — Polar projection. 



concentric circles around the pole, and the meridians take 

 the -form of radiating straight lines. The map-maker is 

 supposed to have his eye at the centre of the globe, and to 

 depict what he sees upon a p'ane which is at the end of 

 the axis, and perpendicular to it. (See the map of the 

 Arctic regions, p. 314.) 



