THE TEADE WIND. 135. 



(59). In examining the figures in these Tables, and the illustrative^ 

 diagrams, it will be seen by Fig. 1, that about the Cape Verde Islands, 

 or that part of the Atlantic most frequently crossed by vessels from Europe,, 

 the mean direction of the Trade Wind is to the Northward of N.E. ; andi 

 further, that Calms and light airs are more prevalent than farther to the- 

 Westward, especially in the summer and autumn months, July to December^. 

 It has always been held that the wind draws more to the Eastward as you 

 get to the Westward of the usual crossing of the Equator, and this an 

 inspection of Fig. 2 will verify, when it is seen that the mean direction is 

 South of E.N.E., and that the Calms, taking the year round, are less 

 frequent. 



Whether the Cape Verde Archipelago has an influence in thus causing 

 the Trade Wind to assume a more Easterly direction to the Westward 

 cannot very well be determined; but it is certain that this E.N.E. direction 

 is not maintained between longitude 40° and the West Indies, as Figs. 3 

 and 4 show that winds hold persistently to the N.E., or a little to the 

 South of it, although winds to the Northward of N.E. are very rare. It 

 is probable, also, that the winds recorded from the other directions are 

 exceptional. 



The Easterly direction of the Trade Wind in the Caribbean Sea will be 

 readily noticed. It will be further remarked on in the observations on the 

 winds of the West Indies, hereafter. 



(60.) The calendar seasons of Northern latitudes are here taken as the 

 quarters of the year. In the American charts these seasons are made to 

 include the month before the usual reckoning ; thus, winter begins with 

 December ; spring, with March, &c. Perhaps the latter mode of division 

 would be rather more applicable to the Tropical phenomena than that here 

 chosen, because it appears that the changes in the inter-Tropical seasons 

 (to which, however, the terms winter, spring, &c., are not applicable) seem 

 rather to coincide with the American calculation. But as these changes 

 are certainly not simultaneous in the Northern latitudes, and, as including 

 such a difference would involve some confusion, the ordinary terms used 

 to designate European seasons is here adhered to as being readily compre- 

 hended and sufficiently exact. 



(61.) The following summary of Trade Winds was given by Commanded 

 Maury, in connection with bis " Wind and Current Chart " : — 



" There is a marked difference in the prevailing direction of the wind, 

 not only according to the season of the year, but also according to different 

 parts of the ocean, including even those parts which are between the same 

 parallels of latitude, but in different longitudes. 



" As a general rule it may be remarked : — 



" 1st, That in the North Atlantic, the nearer to the coast of Africa and 

 the Equator, the more the so-called N.E. Trade Winds haul to the South. 



" 2nd. That to the West of long. 45°, between 20° and 30^ N., the N.E. 

 Trades blow much more steadily in May, June, July, and September, than 

 they do during the rest of the year ; and that during the other months, 

 particularly in March, they blow between these parallels nearly alike from 

 all points of the compass. 



" 3rd. That between lat. 15° and 20°, they are most variable, W^est of 



