358 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. ' " 



August, we find, by 421 observations therein recorded, they had 

 the wind thus : 



Wind from S.E. between Lat. 10^ and 5° S. . with . calms. 



„ S. „ 5° S. and Equator „ , 3 „ 



„ S.W. „ Equator and 5° N. . „ .3 „ 



S.W. „ Lat. 5^ and 10° N. . „ . „ 



69-5. In like manner, and with Hke force, Jansen maintains 

 Lieutenant Jansen. that the uorth-west monsoon of Austraha is the 

 north-east trade-wind turned aside. 



696. The influence exerted upon rainless winds by the deserts 

 Monsoons in the of Africa and the overheated plains of Asia is felt 

 ^'^"^'=- at sea for a thousand miles or more. Thus, though 

 the desert of Gobi and the sun-burned plains of Asia are, for the 

 most part, north of latitude 30°, their influence in assisting to 

 cause monsoons (§ 692) is felt south of the equator (Plate VIII.). 

 So, too, with the great desert of Sahara and the African monsoons 

 of the Atlantic ; also with the Salt Lake country and the Mexican 

 monsoons on one side, and those of Central America in the 

 Pacific on the other. The influence (§ 298) of the deserts of 

 Arabia upon the winds is felt in Austria and other parts of 

 Europe, as the observations of Kriel, Lament, and others show. 

 So, also, do the islands, such as the Society and Sandwich, that 

 stand far away from any extent of land, have a very singular but 

 marked eifect upon the wind. They interfere with the trades 

 very often, and turn them back ; for westerly and equatorial winds 

 are common at both these groups in their winter-time. Some 

 hydrographers have even taken those westerly winds of the Society 

 Islands to be an extension of the monsoons of the Indian Ocean. 



697. It is a curious thing is this influence of islands in the 

 Influences of coral tradc-wiud rogion upon the winds in the Pacific, 

 reefs upon winds. Evory navigator who has cruised in those parts 

 of that ocean has often turned with wonder and delight to admire 

 the gorgeous piles of cumuli, heaped up and arranged in the most 

 delicate and exquisitely beautiful masses that it is possible for 

 fleecy matter to assume. Not only are these cloud-piles found 

 capping the hills among the islands, but they are often seen to 

 overhang the lowest islet of the tropics, and even to stand above 

 coral patches and hidden reefs, "a cloud by day,"' to serve as a 

 beacon to the lonely mariner out there at sea, and to warn him 

 of shoals and dangers which no lead nor seaman's eye has ever 

 seen or sounded out. These clouds, under favourable circum- 



