362 PHYSJCAL GEOGRAPHY OP THE SEA, AND ITS METEOROLOGY. 



declination, but appear to wait until the temperature of the sea 

 water puts it in motion. If a ship which has come into the belt 

 of calms between May and September could lie still in the place 

 where it came into this belt — cast anchor, for example — then it 

 would perceive a turning of the monsoon or of the trade-wind. 

 It would see the belt of calms draw away to the north, and after- 

 wards get the south-west monsoon, or, standing more westerly, 

 perhaps the south-east trade. On the contrary, later than Sep- 

 tember, this ship lying at anchor will see the north-east gradu- 

 ally awake. The belt of calms then moves towards the south, 

 and removes from the ship, which remains there anchored on the 

 north side."* 



676. 27*6 influence oftJie land upon the winds of the sea. — The in- 

 vestigations that have taken place at the Observatory show that 

 the influence of the land upon the normal directions of the wind 

 at sea is an immense influence. It is frequently traced for a 

 thousand miles or more out upon the ocean. For instance, the 

 action of the sun's rays upon the great deserts and arid plains of 

 Africa, in the summer and autumnal months, is such as to be felt 

 nearly across the Atlantic Ocean between the equator and the 

 parallel of 1 3° north. Between this parallel and the equator, the 

 north-east trade-winds, during these seasons, are arrested in their 

 course by the rainy seasons and heated plains of Africa, as obser- 

 vation shows they are in India, and instead of " blowing home " 

 to the equator, they stop and ascend over' the desert sands of the 

 continent. The south-east trade-winds, arriving at the equator 

 during this period, and finding no north-east trades there to con- 

 test their crossing the line, continue their course, and blow home 

 as a south-west monsoon, where they deposit their moisture and 

 ascend. These southwardly monsoons bring the rains which 

 divide the seasons in these parts of the African coast. The 

 region of the ocean embraced by these monsoons is cuneiform in 

 its shape, having its base resting upon Africa, and its apex 

 stretching over till within 10° or 1 5° of the mouth of the Amazon. 

 Indeed, when we come to study the effects of South America and 

 Africa (as developed by the Wind and Current Charts) upon the 

 winds at sea, we should be led to the conclusion — had the foot of 

 civilized man never trod the interior of these two continents — 



* Natuurkiindige Besckrijving der zeeen, door M. F. Maury, LL.D., Lui- 

 tenant der Nord-Araerikaanscbe Marine, vertaald door M. H. Jansen, Luitenant 

 der Zee. (Bijdrage.) Dordrecht, P. K. Braat. 1855. 



