) 



XIX.] THE FIGURE OF THE EARTH. 331 



south, until the figures reach 90°. Hence no place can 

 have a greater latitude than 90°, or a greater longitude 

 than 180°. 



It would be too long a story to explain how latitude and 

 longitude are practically determined. Unless people happen 

 to be mariners, or surveyors, or travellers, they never have 

 occasion to fix their position by these means. But, still, 

 every one is concerned more or less with latitude and 

 longitude, for it is by means of these co-ordinates that we 

 can find out any given place upon a map or a globe. The 

 cross-lines of latitude and longitude form, indeed, a frame- 

 work on which the geographer traces the outlines, which 

 show the distribution of land and water upon the surface 

 of the earth. 



On a terrestrial globe, it is easy enough to lay down the 

 lines of latitude and longitude, and then to draw the outline 

 of any country. But when a map, instead of a globe, is to 

 be made, it is not so easy to see how these lines should be 

 drawn. If the peel were taken off half an orange, it would 

 be found impossible to spread this rounded peel upon a flat 

 table, without the skin giving way at certain points. A map 

 of the world, for this reason, can never give a true repre- 

 sentation of the surface of the earth. 



It was said in the first chapter (p. 5) that a map of the 

 Thames is an outline-sketch of the river, as it might be drawn 

 by a person in a balloon, at a great height, immediately 

 above the place which is mapped. This statement is 

 perfectly true as far as it goes. As long as the man in the 

 balloon looks at the country directly beneath him, he sees 

 it in its true aspect ; but, if he looks a long way off, the 

 curvature of the earth produces distortion in the distant 

 outlines. In one kind of map, however, the person who 

 makes it is supposed to be standing at an immeasurable 



