BAY OF BISCAY. 209 



rain and thick weather, and then gradually veers round to West and N.W,, 

 with clearer weather, and may then, after a day or two, back to the S.W. 

 and blow for several days from that direction. 



Easterly winds occur at intervals, being most common about the Equi- 

 noxes, especially in spring. In June, July, and August, fine weather pre- 

 vails, with light Southerly and S.E. winds, though gales may occur from 

 East or West. In October and Novembej; dense fogs prevail, but seldom 

 last more than 24 hours. 



Northerly winds prevail and are strongest on the parallel of the Pertuis ; 

 thence they decrease in frequency and force in approaching the Pyrenees, 

 and the same in nearing the English Channel. 



The greatest number of days of North-Easterly winds is about on the 

 parallel of the Island of Groix, and on the island itself these winds are 

 much more frequent than those from the S.E. The days of N.E. wind 

 decrease as the Pyrenees are approached. The East winds blow equally 

 throughout. 



The number of days of S.E. wind is greatest at Brest, and least at the 

 Island of Aix ; and the number of days of South wind increases as the 

 Spanish coast is approached ; at Biarritz it is three times as great as at 

 Brest. 



The number of days of S.W. wind is about the same throughout (60 days 

 a year), with a slight increase at Brest, and this wind always brings bad 

 weather. N.W. winds are most frequent at Brest and least so at Biarritz. 



The localities most affected by the different winds depend somewhat on 

 the contour of the coast ; thus, the heaviest S.W. gales are experienced 

 between Brest and the mouth of the Loire ; the heaviest Westerly gales 

 abreast Pertuis and the Gironde district ,■ and the heaviest W.N.W. gales 

 in the lower portion of the bay. 



In summer, the reigning winds on the coast at the head or S.E. angle of 

 the bay, are those from N.E. and East, which become North and N.N.W. 

 in the Gulf of Bilbao. These alternate with N.W. and West winds, which 

 generally drop at night, during which they are replaced by the land breeze. 



In autumn, Southerly winds prevail, and are usually very violent. They 

 last for two or three days, and sometimes for eight or nine days, the weather 

 being clear ; but as soon as they shift to S.S.W., the sky becomes covered 

 with heavy clouds, and almost immediately the " Vendavale " or dirty 

 weather from S.W. and West comes on. This, after some days' duration, 

 passes to N.W., with heavy rains and a stronger sea. This wind, much 

 dreaded by seamen, from the heavy surf which it sends in, and because it 

 debars entrance to the few harbours on the Biscayan coast, is very lasting. 

 It is net uncommon to find it continue for fifteen days consecutively, with 

 only Wr? or three days of even moderate weather. But with this N.W. 

 wind there is no fear of being drifted on to the coast, as it is never entirely 

 hidden, and there are sufficiently clear intervals to allow you to make out 

 the land. 



It is not so with North and N.N.E. winds; they blow perpendicularly 

 on to the coast, and will not allow ships embayed to clear off shore. They 

 completely hide the land, and are accompg uied by much rain and hail, 

 N. A. 0. 28 



