62 : The Atlantic 



ature where the sun is shining will reach 200 degrees Fahrenheit 

 above zero whereas in the shadows or in the dark area o£ the moon 

 it will drop as far below zero. On earth we never carry our climate 

 to quite such extremes, but in the hilly part of the western Sahara 

 Desert the daily temperature variations are extraordinary and un- 

 wary travelers can suffer both from sunstroke and frostbite within 

 twenty-four hours. To a certain degree fluctuation of daily tempera- 

 ture is a feature of all arid deserts remote from the sea. The centers 

 of the continents that are relatively dry are marked by extremely hot 

 summers and extremely cold winters and other features of what is 

 known as a "Continental Climate" — that is to say, a climate so far in- 

 land that it is relatively free from the temperating influence of the 

 ocean. 



It may seem surprising or even doubtful that a stream of water 

 running slowly somewhere offshore, or a surface of water out at sea, 

 could warm the moving winds or even temper the climate of half a 

 dozen nations. It is surprising until we remember the great thermal 

 capacity of water — the capacity to absorb, hold, transport, heat. The 

 texts on oceanography are full of complicated computations on ex- 

 actly what happens when the Gulf Stream cools as it moves along. 

 For general purposes it is enough to remember, as we noted in a pre- 

 vious chapter, that the thermal capacity of air is to that of water 

 about in the ratio of i to 3,000. So it takes 3,000 times as much 

 energy to warm a cubic foot of water one degree as to warm a cubic 

 foot of air one degree. It works the same way in reverse. Thus one 

 cubic foot of Gulf Stream water cooling one degree will raise by one 

 degree 3,000 cubic feet of air. 



Now, referring again to our globe or outline map, notice how 

 the Atlantic and all its supplementary waters invade or surround the 

 European continent with the Black Sea and the Mediterranean, the 

 North Sea and the Baltic. The European continent indeed has the 

 form of a large peninsula, so that almost all parts of it are subject to 

 the modifying effects of the Atlantic waters. These effects are more 

 marked in the northern part of Europe for two reasons. First, be- 

 cause of prevailing westerly winds, and second, because of the sweep 

 of the North Atlantic Drift, which is the natural continuation of the 

 Gulf Stream. Europe is an air-conditioned continent — the Atlantic 

 serving to warm its air, to moisten it and help it to circulate much as 

 machinery conditions the air of a building. 



Because of these same prevailing westerly and southwesterly winds, 

 the effects of the Atlantic are less marked on the American shore 



