6 PHYSIOGRAPHY. [char 



common practice to draw maps in such a position that the 

 north is towards the top, and the south towards the bottom ; 

 while the east lies on the right hand of the person who 

 looks at the map, and the west lies on his left hand. By 

 simply looking then at the map, forming Plate I., it is 

 seen at once that the Thames, though taking — like most 

 rivers — an irregular course, winding first in one direction 

 and then in another, nevertheless has, on the whole, a west- 

 and-east course ; it flows, in short, from the west towards 

 the east. At the same time it is seen that the left side of 

 the river is its northern bank, and the right side its southern 

 bank. It is clear, too, that the tributaries on the left or 

 north side flow generally from north to south, whilst those 

 on the right or south side run generally from south to 

 north. 



These terms — north and south, east and west — are terms 

 which have a meaning quite independent of local circum- 

 stances, and indicate definite directions which can be 

 determined in any part of the world and at all times. 

 When, in the early part of this chapter, we used the local 

 expressions " up the river " and " down the river," " above 

 bridge" and " below bridge," it was assumed that the reader 

 was familiar with the Thames. But to a perfect stranger, 

 one who had never seen the river and knew nothing of 

 London Bridge, such a method of description would be 

 unintelligible. By employing, however, the terms north 

 and south, east and west, we are using expressions that 

 are familiar to all educated people, since they refer to 

 standards of direction universally recognised. It is de- 

 sirable to explain how these cardinal points may be 

 determined. 



Of the four points, the south is perhaps the most easily 

 found, at least on a sunshiny day. Ever/ morning the sun 



