CHAPTER X 



THE HYDROSPHERE 



214. Land and Water. The hydrosphere does not 

 completely cover the globe, because the lithosphere which 

 supports it is diversified by great heights and hollows. 

 The portion of the heights projecting above the water 

 surface forms land, which is estimated at the present time 

 to cover 28 per cent or a little more than one quarter of 

 the globe. Most of the hydrosphere is retained in the 

 great world-hollows forming the ocean, which covers about 

 7 2 per cent of the surface ; 

 but on account of evapora- 

 tion and condensation a 

 small part is always present 

 as vapour in the air, and 

 a larger amount rests as 

 lakes in hollows of the land 

 or flows across the surface 

 in rivers. The proportion 

 of land and water in differ- 

 ent latitudes is represented 

 in Fig. 31, where the land 

 area is indicated by shad- 

 ing. The largest propor- 

 tion of land is in the 

 northern hemisphere, where 



FIG. 31. Proportion of land and sea in 

 different latitudes. Land area shaded 



(after Krummel). 



it occupies about 42 per cent of the surface, while water 

 largely predominates in the southern hemisphere, where 



