64 : The Atlantic 



the warm water that is flowing north and south and being driven by 

 the belts of trade winds has to be replaced by colder water coming 

 up from lower levels of the sea. On the other hand, in northern lati- 

 tudes, wherever and whenever surface water is relatively warm and 

 the air cold, there will be a high rate of evaporation usually visible as 

 mists or fog. This effect is not confined to the ocean and we can re- 

 member it any time that we care to look at the smoking surface of a 

 mountain lake in the early autumn. Before we leave this section it 

 will be worth noting that in the Western Hemisphere the Atlantic 

 contributes water content to the air over the land chiefly in the trop- 

 ics and the great trade wind belts. On the other hand, on the Euro- 

 pean side, the Atlantic contributes its moisture chiefly in the region 

 of the prevailing westerlies. This should make it clear that the areas 

 of land that largely receive their precipitation from the Atlantic have 

 a quite different pattern from that of the areas of land that contribute 

 their drainage to the Atlantic. 



The preceding functions of an ocean may be considered as natural 

 functions — those that are world-wide in character and that create the 

 general conditions of human life. To these we may add a set of func- 

 tions from which man benefits directly and in which he directly par- 

 ticipates. It will be enough to refer to each of them briefly in this 

 place in order that we may have a summary of the major character- 

 istics of the Atlantic. How these functions have operated in detail 

 and how they have served man in the past form part of the stories 

 and histories in the next section of this book. 



Food: Wherever man has lived on the seashore or adjacent to the 

 sea, it has supplied an important part of his living resources. Even 

 the most ancient and primitive people have derived the most impor- 

 tant part of their food supplies from the sea. The inventive and in- 

 genious Eskimos serve as a particular example since they have de- 

 rived from fish and animals of the sea practically their entire diet. 

 At the same time, the sea animals have supplied them with oil for 

 warmth and illumination, furs and skins and membranes for their 

 clothing, bedding and the lining for their houses and even bones 

 and ivory for their weapons, their ornaments and their arts. They are 

 perhaps an extreme example. 



Almost any part of the sea will sustain a reasonably large popula- 

 tion along its shores and supply them adequately with foodstuffs that 

 are not only nutritious but also contain all the required vitamins and 

 minerals. In such a diet shellfish, crustaceans and small shore fishes 

 play an important part. Through most of history the sea has made a 



