458 APPENDIX 



lie flat, and if crushed into this shape, it will break into 

 pieces and only partly cover the surface over which it 

 spreads. The same is true of any curved surface. Thus 

 the continents of the earth, if they were flattened out, 

 would of necessity be broken into fragments. If they 

 could not themselves be made to occupy a flat surface, 

 then no accurate map of them can be made on such a sur- 

 face. 



Although there are several ways of representing a 

 curved surface upon a flat surface, yet no method has been 

 found which is perfectly satisfactory. If the areas are in 

 the right proportions, the outlines are not; and when the 

 outlines are right, the areas are not. These different ways 

 of mapping the surface of the earth are called projections. 

 As a large part of our knowledge of the earth's surface is 

 obtained from maps, it is very essential to have some idea 

 of how these maps are made and wherein the essential 

 error of each consists. Two very important kinds of pro- 

 jection are the cylindrical and the stereographic. 



221. Cylindrical Projection. In this .projection it is con- 

 sidered that a cylinder is wrapped around the globe touch- 

 ing at the equator. The points on the globe are projected 

 on to the cylinder by lines drawn from the center of the 

 globe through each point to the surface of the cylinder. 

 Thus the meridians become straight lines always the same 

 distance apart ; and the parallels of latitude are also 

 straight lines, but their distances apart will increase with 

 the latitude. The poles themselves, being in the diameter 

 of the cylinder, lie at an infinite distance from the equator. 



When such a cylinder is unrolled it forms a skeleton 

 map on which can be plotted places whose latitude and 

 longitude are known. The directions north and south wilF 

 be up and down the map, and east and west to the right 

 and left. This cylindrical projection causes a degree of 



