3G0 niVSICAL GEOGKArUY OF THE SEA, AND ITS 3IETE0R0L0GY. 



to extend with its influence no farther than thirty degrees of 

 hititude. The fact also favours the idea suggested by the 

 diagram (§ 071), tliat the mean height of the barometer in the 

 polar calms is very much less than it is in the cquatoriah More- 

 over, the counter trades of the southern hemisphere are very 

 much stronger (§ 026) than the counter trades of the other. 

 They are also stronger than the trade-winds of either; these 

 iticts likewise favour the idea of a greater exhaustion of air 

 in the antarctic than in the arctic calm place ; and it is mani- 

 fest that actual observations also, as far as they go, indicate 

 such to be the case. In other words, " the brave west winds " of 

 the southern hemisphere have the greatest "barometric descent," 

 and should therefore be, as they are, the strongest of the four 

 winds. 



673. Study of the monsoons affords farther information touching the 

 calm belts. — Farther information may be gained upon the subject of 

 high and low barometers, of the " barometric declivity of winds," 

 and of the meteorological influence of diminished atmospheric 

 pressure by studying the calm belts in connection with the 

 monsoons. 



674. The south-icest winds of the Atlantic. — Before, however, we 

 proceed to these, let us take a hasty glance at the winds in cer- 

 tain other parts of the ocean. The winds which most prevail on 

 the polar side of the calm belt of Cancer, and as far as 50° N. in 

 the Atlantic, are the west wands. " Wind and weather in this 

 part of the ocean," saj^s Jansen, " are very unreliable and change- 

 able ; nevertheless, in the summer months, ^ve find permanent 

 north winds along the coast of Portugal. These north winds are 

 worthy of attention, the more so from the fact that they occur 

 simultaneously with the African monsoon, and because we then 

 find northerly winds also in the Mediterranean, and in the Ked 

 Sea, and farther eastward to the north of the Indian monsoon. 

 When, between the months of May and November, during which 

 the African monsoon prevails, the Dutch ships, which have lin- 

 gered in the calm belt of Cancer run wdih the north-east trade, 

 and direct their course for the Cape Verd Islands, then it seems 

 as if they were in another world. The sombre skies and change- 

 able — alternately chilly and sultry — w^eather of our latitudes ai'e 

 replaced by a regular temperature and good settled weather. 

 Each one rejoices in the glorious heavens, in which none save 

 the little trade-clouds are to be seen — which clouds in the trade- 



