CLIMATE 13 



surface, they must also become drier. We perceive this 

 well enough in the case of our own east winds. 



5. Ocean-Currents.— These have a marked influence 

 on climate. The Gulf Stream spreads as a drift over the 

 surface of the North Atlantic Ocean, moving in a north- 

 easterly direction towards the shores of Western Europe, 

 to which it brings the stores of heat and moisture which 

 it has drawn from tropical seas. The chmatic effect 

 of the Gulf Stream is, however, mainly attributable to 

 the winds that accompany it in its long journey from the 

 Tropics. Owing to the presence of these winds, the 

 fiords of Norway are free from ice all the winter, even up 

 to the Arctic Circle, while on the other side of the Scan- 

 dinavian Mountains, the Baltic Sea, exposed to the dry 

 cold winds of Northern Russia, is frozen over for several 

 months in the year. 



6. Presence of Clouds and Fogs. — ^Where these con- 

 stitute a characteristic feature of the climate, the weather 

 is raw and cold. Clouds and fogs form an effective 

 barrier to the sun's rays, and the soil, thus screened, loses 

 much of the warmth that otherwise would reach it. 

 Scotland is, for the most part, such a country. Holland, 

 too, is cold and foggy. In Tierra del Fuego, in certain 

 oceanic islands like the Falklands, and in the lonely 

 island of Kerguelen in the Indian Ocean, the sun is 

 rarely visible through the clouds. 



7. The Destruction of Forests. — Even in nature, 

 forests may occasionally be destroyed by fire, but in 

 most cases their disappearance is due to their deliberate 

 removal by man. As a result, the atmosphere in these 

 localities has become drier; on sloping ground the rain 

 runs off instead of soaking in; the soil gets washed away; 

 and the fertility of the land is destroyed. On the other 

 hand, afforestation tends to increase humidity and 

 restore fertility to the whole district. Thus, between 

 1863 and 1878, trees were planted on 19,500 acres of 

 barren land on the stony slopes of Ventoux, in Provence, 

 France. These forests yielded £2,800 a year in 1911, 

 a sum which was expected to increase to £3,600 in five 

 years' time. But far more important than this is the 

 accompanying statement that " springs have reappeared, 

 the lower lands have increased in value, and the village 

 proprietors have found themselves suddenly enriched," 



