372 THE PHYSICAL GEOGRAPHY OF THE SEA. 



Influence of coral ^01 who has ciuised in those parts of that ocean has 

 reefs upon winds, q^iq^ tumed with wondei and dehght 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 cap- 

 ping the hills among the islands, but they are often seen to over- 

 hang 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 or seaman's eye has ever seen or 

 sounded out. These clouds, under favorable circumstances, may 

 be seen gathering above the low coral island, and performing 

 their office in preparing it for vegetation and fruitfulness in a 

 very striking manner. As they are condensed into showers, one 

 fancies that they are a sponge of the most delicately elaborated 

 material, and that he can see, as they "drop down their fatness," 

 the invisible but bountiful hand aloft that is pressing it out. — 

 Maury's Sailing Directions^ 7th ed., p. 820. 



698. Land and sea breezes are monsoons in miniature, for they 

 Monsoons in minia- depend in a mcasurc upon the same cause. In the 

 *"''®- monsoons, the latent heat of vapor which is set 

 free over the land is a powerful agent. In the land and sea 

 breezes, the heat of the sun by day and the radiation of caloric by 

 night are alone concerned. In the monsoons the heat of summer 

 and cold of winter are also concerned. But could the experiment 

 be made with two barometers properly placed — one at sea and 

 the other on land, but both within the reach of land and sea 

 breezes — they would show regular alternations. In the sea 

 breeze the land barometer would be low and the sea high, and 

 vice versa in the land breeze ; and when the barometer was high- 

 est and when it was lowest it would be calm. 



699. It is these calm bands or "medial belts," as the crest and 

 The changing of the trough of the baromctric wave may be called, 

 monBoons. which, with their canopy of clouds, follow the de- 

 parting and herald the coming monsoon. They move to and fro, 

 up and down the earth, like the sun in declination. As they 

 have a breadth of 200 or 800 miles, they occupy several days in 

 passing any given parallel, and while they overshadow it, then 

 the monsoons are dethroned. During the interregnum, which 



