THE ANTI-TRADES OR PASSAGE WINDS. 197 



iu the remaining portion of the track frequently breaks in as a N.E. wind. 

 In both cases it seeks out the warm S.W. air current which accompanies 

 the warm Gulf Stream, and impinges on it at right angles, bringing the 

 wind vane quickly round, and it is followed by hail and sleet if the North 

 wind lasts, and by snow if the South wind returns. The barometer alter- 

 nately rises and falls while these invasions of the N.W. wind into the 

 region of the S.W. current, which is continually flowing on, are constantly 

 repeated, until at length the force of one current or the other enables it 

 to put an end to the struggle, at least for a time. In winter, the truce is 

 never of long duration. As soon as the differences of tension have again 

 become large enough, the conflict and the alternate displacement is 

 renewed. 



The majority of Storms occur between long. 30° and 55° W., being 94 

 more than in the equally large space between 30° and 5° W., and 241 more 

 than in the district from 55° to 74° W., which is only 6° narrower. But 

 in this last third of the route, N.E. Storms are much more prevalent than 

 in the other sections, whilst in the first third, outside the Channel, the S.E. 

 Storms occur remarkably often ; in the last third, however, they do not 

 disappear nearly so completely as the S.W. Storms do. 



It is clear, however, that in the practice of steam navigation to and from 

 America, the Polar or Equatorial gales which allow a ship to lay her course 

 are less important than the Westerly or Easterly. Counting the total 

 number of N.W. and S.W. Storms as Westerly; and the N.E. and S.E. 

 Storms as Easterly ; we find that three-fifths of the Storms are from S.W. 

 to N.W., and one-third of the whole number take place in the three winter 

 months : on the other hand, about one-sixth of the total number blow from 

 an Easterly and Northerly direction respectively ; and only 6 per cent, 

 from a Southerly direction. 



In examining the Tables to see whether the occurrence of Storms depends 

 in any way upon the latitude, it will be found that in December and Feb- 

 ruary the region of Storms, as far West as 35° W., lies uniformly about 

 50° N. ; from 35° to 77° W., decidedly between 50° and 45° N. In January, 

 as far as 35° W., to the North of 50° N. ; from 35° W., first North then 

 South of 45° N. In March, decidedly between 50° and 45° N. 



In April it is more uniformly distributed from above 50° N. to South of 

 45° N. In May, between 45° and 50° N., but on the whole there are but 

 few Storms. In June, North of 50° N. In July and August, between 45° 

 and 50° N. 



In September it is uniformly distributed ; but the number of Storms is 

 increasing. In October, from 50° N. to 40° N. In November, North of 

 50° N. to 35° W., and afterwards pretty uniformly distributed ; generally 

 in October and November, no great differences observable in the distribu- 

 tion. 



Between lat. 40° and 45° N., and long. 55° and 74° W., Storms prevail 

 from October to March, being strongest in January ; from April to Sep- 

 tember they very seldom occur in that district. 



Referring to a remark that the cold Polar Current between 40° and 55° W. 

 forms the reservoir for the N.W. and N.E. Storms which break out from 

 that region, it is by no means to be inferred therefrom that all N.W. Storms 



