NORTH PACIFIC 89 



the late winter (to about latitude 30° N.) than in the Atlantic (only 

 to about latitude 35° N.). 'High seas are also considerably more fre- 

 quent in middle and low latitudes in the western side of the Pacific, 

 from southern Japan to the northern Philippines (5 to 28 percent) 

 than they are in the corresponding belt in that side of the open North 

 Atlantic, i. e., from northern Florida to French Guiana (2 to 11 per- 

 cent). Other than this, however, the winter seas of the Northeast 

 Trades average high about equally often in the one ocean as in the other, 

 except that the east-west gradation is, of course, condensed within a 

 much shorter distance in the North Atlantic than it is in the North 

 Pacific ; and the Doldrum Belt is smooth about as constantly in the one 

 ocean, off equatorial West Africa, as it is in the other, of Central 

 America. 



The increase that takes place in the frequency of high seas, through 

 the autumn in middle and high northern latitudes is mirrored so 

 closely in the swell that by midwinter the latter runs high during 

 40 to 60 percent of the time throughout the north central portion of 

 the Pacific as a whole. Indeed, the only extensive regions where the 

 swell has not been definitely reported "high" during at least 10 per- 

 cent of the time, for the open North Pacific in February, are in its 

 western side from southern Japan southward along the Philippines, 

 and in the general offing of the American coast in the east, from south- 

 ern California to the equator. It is probable, however, that this also 

 applies to the equatorial belt, westward from about longitude 180°, 

 for a high swell was reported in only 1 out of 62 returns that were 

 received thence for January and February. 



Corresponding to this greater frequency of high swells, low swells 

 are encountered considerably less often over the Pacific as a whole, 

 southward to the latitude of middle Japan in the one side and to that 

 of middle California in the other, in February (9 to 44 percent) than 

 in August (34 to 80 percent) ; this applies also in the Trades, and 

 along the equatorial belt in the west, wherever, a significant number 

 of reports have been received. 



On the other hand, the smooth area in the American side of the 

 equatorial Pacific, where the swell is low during more than four-fifths 

 of the time, is much more extensive in winter than in summer (con- 

 tours for 80 percent low swells, pis. XII and XVI). A. swell, larger 

 or smaller, is, however, mentioned in 70 to 90 percent of the winter 

 returns, except along Japan, as well as here and there perhaps in the 

 equatorial belt in the west, and locally in the Panamanian region in 

 che east. Hence it appears that no considerable part of the open 

 Pacific is ever wholly free from a swell at this time of year, a low one 

 being so inconspicuous a phenomenon that it is apt to be ignored, 



