PHYSICAL GEOGRAPHY 275 



699.2 mm.; at Beruijord during a period of 34 years, from 788.7 mm. 

 to 704.9 mm.; and at Akureyri, during one of 33 years, from 789 mm. 

 to 705.7 mm. The paths of the moving centres of depression lie especi- 

 ally frequently south of Iceland so that one centre of depression after 

 the other crosses the Atlantic from the west with a main direction of 

 east or north-east; sometimes nearer, sometimes further from Iceland. 

 This movement of low pressure centres causes the wind to veer to- 

 wards the sun, especially from S. or SE. through E. and NE. Table III 

 shows that at Stykkisholm, very frequently the winds blow from S. 

 and SW. (such form 11 /o and 10 /o respectively) which is due to the 

 fact that Denmark Strait also provides a path lor the moving centres 

 of depression ; they come from the south and cause on Iceland a veering 

 of the wind with the sun from SE. or S. through SW. It is probably 

 these centres of depression which cause the rather frequent winds from 

 the W. and SW. at Grimsey and Papey respectively. There may, 

 however, occur longer periods in which the winds of Iceland are 

 rather constant, the lowest atmospheric pressure over the North 

 Atlantic remaining at the same place. The wind-conditions are gen- 

 erally favourable for Iceland, the warm air from the Atlantic Ocean 

 is carried in over the land, while it is rare for cold winds to be 

 thus brought during winter. According to observations taken at 

 Stykkisholm on the west coast, the warmest winds there are the 

 SE., S. and SW. while the greatest cold is caused by the N., NE. 

 and E. winds. The difference between the temperature induced by 

 the warmest and bv the coldest winds is on an average 9 10 C. 



*/ 



in the months of December to April, and 4 6 C. in the other 

 months. The temperature may show great differences according to 

 whether northerly or southerly and easterly winds are the prevalent 

 ones for any length of time; thus, the mean temperature at Stykkis- 

 holm in March 1856 was 4- 4.3 when southerly winds prevailed, 

 and in March, in the ice-year 1881, the mean temperature was 

 13.3 when easterly winds were prevalent. 1 Conditions pertaining 

 to the atmospheric pressure over the Atlantic, which is specially 



1 V. Willaume-Jantzen : Climat du littoral islandais, 1902. N. Hoffmever: 



+f 



Die Vertheilung des Luftdruckes uber den nord-atlantischen Ocean wahrend des 

 Winters und deren Kinfluss auf das Klima von Europa (Zeitschrift fur Meteorologie. 

 Wien, 1878. Bd. XIII. Nr. 22). N. Hoffmever: Etude sur les tempetes de TAtlantique 

 septentrional. Copenhague, 1880. G. Rung: Repartition de la pression atmos- 

 pherique sur 1'ocean atlantique septentrional. Copenhague, 1894. V. Garde: Vind- 

 kort over den nordligste Del af Atlanterhavet ' Nautisk-meteorologisk Aarbog for 

 1899. Kebenhavn, 1900. S. 25-46). 



