DISCUSSION AND ANALYSIS OF WINDS. 



713 



Between 55° and 60° it is lower than around Iceland, the lowest known in the 

 northern hemisphere. The great permanence and strength of the westerly winds 

 in the southern temperate zone is explained by this. (See Plates 5, 6, and 14.) 



NORTHWESTERN EUROPE. 



The islands to the N. W. of Europe have still the climate of the Atlantic Ocean. 

 Only one of them, the largest and most northerly, Iceland, has some of the charac- 

 teristics of the polar zone. 



Near Iceland, on account of the heated current of the gulf-stream, is the lowest 

 pressure of the northern hemisphere, and though it is especially marked in autumn 

 and winter it is also conspicuous at the other seasons. As is to be expected from 

 a country in such a position, the winds are very changeable, according to the shift- 

 ing of the centre of lowest pressure to the north and south. The equatorial winds, 

 S. W., and the polar, N. E., prevail in turn. 



The Faroe islands have prevailing S. W. winds at all seasons. This is even 

 more the case at the Shetland islands, and in Great Britain generally, as is shown 

 by percentages in the next table. 







Summer. 



Winter. 





« 





H 





^ 





^ 





p4 





W 





^ 





^ 







K 



fc 



W 



m 



m 



m 



^ 



fe 



fc 



fe 



H 



m 



rA 



m 



i 



fe 



Zone 5. 



N. 15. Stykkisliolm, N. W. Iceland 



4 



17 



27 



11 



13 11 



9 



9 



2 



25 



25 



15 



12 



13 



6 



2 



" B. 



N. 19. Reikiavik, W. Iceland. 



IB 



12 



9 



21 



16 14 



7 



5 



13 



29 



19 



10 



2 



22 



3 



2 



" 6. 



N. 21. Tlioi-shavu. Faroe Islands . 



11 



11 



7 



10 



8 26 



IS 



8 



10 



12 



7 



13 



12 



23 



14 



10 



6. 



N. 22, 23. Shetland Islands . 



11 



11 



6 



10 



12: 20 



19 



12 



12 



8 



4 



12 



13 



25 



16 



10 



" 7. 



N. 27. W. Scotland, 5B°-59= N. 



10 



9 



11 



6 



9 26 



IS 



11 



7 



7 



8 



7 



13 



30 



18 



10 



7. 



N. 29, 31. W. Scotland, 56°-58° N. 



6 



8 



11 



7 



11: 23 



23 



12 



6 



11 



8 



12 



7 



24 



22 



9 



« 7. 



N. 33. W. Scotland, 55°-56 N. 



6 



9 



9 



9 



91 23 



23 



12 



5 



10 



10 



10 



6 



24 



22 



11 



" 7. 



N. 89 and 43. E. Scotland, 56°-58° N. 



8 



9 



11 



9 



13 22 



16 



12 



8 



6 



5 



8 



10 



28 



23 



12 



8. 



N. 39. Ireland, 53°-54° N. . 



8 



11 



7 



9 



8 



13 



24 



IS 



7 



5 



6 



10 



13 



17 



24 



18 



" 8. 



N. 44 and 48. Ireland, 51°-53° N. . 



8 



5 



4 



7 



10 



20 



20 



25 



8 



11 



6 



11 



13 



22 



13 



16 



« 8. 



N. 113. Greenwich, S. E. England . 



10 



13 



^ 



6 



9 



36 



13 



7 



11 



11 



6 



6 



12 



32 



12 



7 



There is little difference between the winds in winter and summer, from Faroe 

 islands to southern England. A very slight one only can be detected in the greater 

 number of W. and N. W. winds in summer. This applies not only to Great 

 Britain, but also to the greatest part of northern and central Europe. It is due 

 to two causes: First, the belt of highest barometer is more northerly in summer 

 than in winter; and second, part of the air is attracted towards the depression of 

 Central Asia. 



In Great Britain the influence of the last cause is very small, as Central Asia is too 

 distant, and the depression about Iceland so near, that it must act very powerfully 

 even in summer. But the further we advance eastward the greater is the influ- 

 ence of the depression in Central Asia, and consequently the greater the difference 

 between the direction of the wind in winter and summer. The next table gives 

 the mean direction of the wind in Great Britain and Iceland. 



90 July, 1875. 



