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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 70 



have taken the values of the highest and lowest isobars in these two 

 action regions. Since the so-called Icelandic minimum in individual 

 months may include two or three subordinate areas of minima, it is 

 difficult to decide which of them shall be chosen in order to reach 

 the desired homogeniety in the investigations. The most strongly 

 marked minimum in an individual month may be wholly within the 

 Barents Sea or even be forced over to the Kara Sea, or on the 

 other hand it may be in Bafifin's Bay or within the North American 

 Arctic Archipelago. Still, only in exceptional cases the choice be 

 doubtful. 



M95 im IM. WIO 



Figure 93. Monthly means. I : the anomalies of the air pressure differ- 

 ences of the North Atlantic. II : the anomalies of the surface temperature 

 in fields 30° to 39° west, 50° to 53° north, scale inverted. Ill : the same for 

 the field 20° to 29° west, 53° to 57° north, scale inverted. IV : the same for the 

 field from 0° to 9° west 58° to 59° north. 



In curve IV, figure 92, we give the ..observed monthly values of 

 the air pressure difference in the North Atlantic Ocean for the 

 period 1885 to 1910. In curve V we give the monthly variations in 

 the air temperature in all Norway. In figure 93 are shown by curve 

 I, the monthly variations in the air pressure difference, and in curves 

 II and III the monthly variations in the surface temperature in the 

 Danish fields at 30° to 39° west longitude and 20° to 29° west longi- 

 tude, both curves being inverted. Finally in curve IV we give 

 those of the fields 0° to 9° west longitude. In figure 94 we have 

 given the curves of the above mentioned air pressure difference in 

 the North Atlantic, the air temperature in all Norway and the sur- 

 face temperature in the three Danish fields, all smoothed by consecu- 

 tive twelve-monthly means. 



