NORTH ATLANTIC 79 



from December through February as well as from June through 

 August). And the sea ranges low for nearly or quite two-thirds of 

 the time by the end of the winter, not only along equatorial West 

 Africa as is the case in summer, but westward thence, as well, right 

 across to the longitude of eastern Brazil (See the contours for "low 

 seas" with 60 percent frequency, pis. II and VI) following on the 

 autumnal migration southward of the Southeast Trades. 



We have only one report of the state of the sea in the Gulf of St. 

 Lawrence for January, none for February. And in any case, there is 

 so much drift ice in the Gulf toward the end of the winter that scat- 

 tered data would be of little significance there. 



High seas are somewhat more frequent in the Caribbean during 

 January and February (2 to 13 percent) than in August (0 to 11 per- 

 cent), corresponding to the fact that the Trades average somewhat 

 stronger there in winter than they do in summer, though the sea is re- 

 ported "low" about as frequently there at the one season as at the other 

 (22 to 51 percent in summer, 21 to 38 percent in winter) . The sea, too, 

 is usually much the smoothest close under the shelter of the Lesser 

 Antilles, of the Virgin Islands, of Puerto Rico, of Hispaniola, of 

 Jamaica, and of Cuba, and the roughest off the coasts of Colombia, 

 of Costa Rica, and of Nicaragua, in winter as well as summer, 

 which is to be expected, since the Trades are the governing winds over 

 the Caribbean the year round. The seasonal succession is similar to 

 this in the Gulf of Mexico, where the stronger winds of winter, with 

 occasional gales of moderate strength, generate high seas during 2 to 7 

 percent of the time and most often in the general vicinity of Tampico, 

 with the corollary result that one is considerably less apt to find the 

 sea low there during the winter (45 to 68 percent) than at the end of 

 the summer (70 to 91 percent). 



An interesting corollary of the stormy weather of winter is that 

 the swell runs high considerably more often at that season than the 

 sea does, wherever a high sea is a common event. The most striking 

 illustration of this rule is to the northward, as illustrated by the much 

 wider areas enclosed by the successive contours for high swells (pi. 

 VII) than by the corresponding contours for high seas (pi. V). 



This predominance of high swells over high seas in the stormier 

 latitudes of the North Atlantic probably results from the fact that 

 the swells resulting from the seas raised by one storm are followed so 

 soon by the swells from the next, that the surface of the ocean is never 

 free from them. Similarly, the swell runs high nearly twice as often 

 in winter (20 to 30 percent) as the sea does (13 to 18 percent) in the 

 downwind part of the Northeast Trades, no doubt because seas are 

 so soon transformed into swells, if the wind slackens temporarily. 



