THE WEST INDIES. 141 



(63.) — Winds of the Atlantic Islands.— Tlie winds upon and near the 

 different islands in the Atlantic Ocean are very variable and uncertain, 

 especially where the land is high and irregular. In general, regular sea 

 and land-breezes alternately prevail; the Sea-breeze by day and the Land- 

 breeze by night, as the land is alternately heated and cooled ; but the 

 direction of these breezes is varied by the quahty and figure of the land, 

 and other local circumstances. If the land be very high, it generally 

 intercepts the prevailing wind, and so affects the air as to produce, on the 

 lee-side, either a calm, a gentle breeze in an opposite direction, or a kind 

 of eddy, which is sometimes very troublesome to sailing ships. Such is 

 the case under the Western part of Madeira, and to leeward of the Canary 

 Islands. The Grand Canary is so high as to stop the current of the N.E. 

 wind which prevails there ; and on the Eastern side there is a calm, or a 

 gentle breeze from S.W. 



The calms and eddy winds, occasioned by the figure and height of the 

 Canaries, extend from 30 to 90 miles beyond them to the S.W., according 

 to the height of the respective islands. The boundary of the calms may 

 be seen, for, within them, the water is smooth ; without them is the 

 regular undulation of the sea, caused by the general wind; and at the end 

 of them, the winds, by setting in opposite directions, produce a breaking 

 of the waves with a foam, like the biUows on a rocky shoal just beneath 

 the surface of the ocean. 



From a consideration of the particulars now described, the cause of those 

 copious dews which fall in the night on the islands, &c., situated within 

 the Tropics, will be apparent. For as the great power of the sun by day 

 causes an extraordinary evaporation of the water of the ocean, so, in the 

 night, the exhalation, ceasing to retain the same degree of levity acquired 

 from the heat of the sun, becomes, by the absence of the power which 

 produced it, so dense and heavy as again to fall back to the earth. The 

 air at the same time cooling, by the same cause, is also affected by the 

 descending moisture, and thus acquires an additional tendency to increase 

 the land-breeze. 



(64.) West Indies. — The following description of the winds prevailing 

 over these regions in general, in the different seasons, is taken chiefly from 

 Captain Livingston's translation of the " Derrotero de las Antillas," or 

 Spanish Directory for the West Indies. 



On the Eastern coasts of Central America, and among its islands, the 

 course of the general Easterly or Trade Wind is uninterrupted, though 

 subject to some modifications in direction and force. At a short distance 

 from the land the sea-breeze calms at night, and is replaced by the land- 

 breeze. This variation happens every day, unless a strong wind prevails 

 from the Northward or Southward ; the first of these being experienced 

 from October to May, and the second in July, August, and September. 



The general Easterly wind, of the Tropical regions, is felt on the coast 

 of Guayana, and on the coasts of the Caribbean and Mexican Seas, but 

 with variations which may be denominated diurnal and annual. The 

 diurnal period is that caused by the sea-breeze, which strikes the coast 

 usually at an angle of two points, less or more, from a right angle, accord- 

 ing to the locality and other circumstances ; and then the land-wind, 



