xyn Man in Nature 337 



or governments, usually without the consent of the people 

 concerned, have drawn most of the boundary lines on 

 " political " maps. Historical Geography concerns itself 

 with tracing out the changes in the extent of territory 

 exclusively occupied or controlled by each nation at 

 different times. 



431. Man's Power in Nature. Man more than any 

 other animal leads a destructive life. The use of wood in 

 construction and for fuel enables him to destroy forests so 

 rapidly that in comparison the depredations of beavers and 

 all other animals are insignificant. The need for com- 

 munication between distant parts of the Earth has pro- 

 duced considerable changes in the configuration of coasts 

 and in the distribution of land and water. Plants and 

 animals also have been modified by cultivation, and their 

 natural limits of distribution entirely altered. Much of 

 Man's power in Nature is evasive. It consists in devising 

 methods of utilising natural phenomena for the purpose of 

 escaping uncomfortable consequences. Thus the invention 

 of the umbrella and of the sun -helmet give a certain 

 amount of independence of the weather ; still more the 

 methods of heating, cooling, and lighting houses. Light- 

 ning conductors reduce the risk to which life and property 

 are exposed in a thunderstorm ; knowledge of the laws of 

 cyclone - motion often enables sailors to escape the 

 fury of a storm. Steam-engines on land and sea, and 

 above all the electric telegraph, deprive wide tracts of the 

 Earth's surface of their natural influence as barriers. But 

 in every case natural powers are not overcome ; they are 

 merely utilised. 3 



432. Geographical Changes. When land becomes 

 valuable it is often profitable to reclaim ground from the 

 sea. This is done along the flat coasts of most civilised 

 countries, and to an unequalled extent in Holland, where 

 most of the people actually live below sea-level. The sea 

 is kept out by a grand system of artificial dykes and regu- 

 lated sand-dunes, while continual pumping by steam or wind 

 power keeps the water-tight compartments of the reclaimed 

 land dry. On the other hand, there are many projects for 



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