GEOGRAPHICAL DISTRIBUTION. 153 



The same powers that raised the chains of the Andes and 

 the Himalaya to the regions of perpetual snow, have occasioned 

 new compositions and new textures in the rocky masses, and 

 have altered the strata which had been previously deposited 

 from fluids impregnated with organic substances. We here 

 trace the series of formations, divided and superposed accord- 

 Ing to their age, and depending upon the changes of configu- 

 ration of the surface, the dynamic relations of upheaving forces, 

 and the chemical action of vapours issuing from the fissures. 



The form and distribution of continents, that is to say, of 

 that solid portion of the Earth's surface which is suited to the 

 luxurious development of vegetable life, are associated by inti- 

 mate connexion and reciprocal action with the encircling sea, 

 in which organic life is almost entirely limited to the animal 

 world. The liquid element is again covered by the atmosphere, 

 an aerial ocean in which the mountain- chains and high plains 

 of the dry land rise like shoals, occasioning a variety of cur- 

 rents and changes of temperature, collecting vapour from the 

 region of clouds, and distributing life and motion by the action 

 of the streams of water which flow from their declivities. 



Whilst the geography of plants and animals depends on 

 these intricate relations of the distribution of sea and land, the 

 configuration of the surface, and the direction of isothermal lines 

 (or /ones of equal mean annual heat), we find that the case is 

 totally different when we consider the human race the last 

 and noblest subject in a physical description of the globe. 

 The characteristic differences in races, and their relative nu- 

 merical distribution over the Earth's surface, are conditions 

 affected not by natural relations alone, but at the same time 

 and specially, by the progress of civilization, and by moral 

 and intellectual cultivation, on which depends the political 

 superiority that distinguishes national progress. Some few 

 races, clinging, as it were, to the soil, are supplanted and 

 ruined by the dangerous vicinity of others more civilized 

 than themselves, until scarce a trace of their existence 

 remains. Other races, again, not the strongest in numbers, 

 traverse the liquid element, and thus become the first to 

 acquire, although late, a geographical knowledge of at least 

 che maritime lands of the whole surface of our globe, from 

 pole to pole. 



I have thus, before we enter on the individual characters of 



