254 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. "JO 



southwesterly winds in the most northerly Atlantic Ocean and 

 Europe, would produce an increase of temperature in these regions. 

 This increased circulation would, however, at least as a rule, act in 

 an opposite direction in the northern central parts of the North 

 Atlantic Ocean, though the result depends obviously to a certain 

 degree on the direction of the winds, as we have already said. Fur- 

 thermore an intensification of the trades, which is associated with 

 the increase of the air circulation, as mentioned above, would have 

 the effect of causing the temperature of the ocean surface and of 

 the air in the trade regions to fall. 



As we have already said, the curve for the most westerly Danish 

 field shows great similarity with the temperature curves of the same 

 time interval for a series of meteorological stations in different 

 parts of the earth, while on the other hand the Scandinavian curves 

 show for many years similarity with temperature curves for other 

 stations. From this w'e conclude that the observed variations in the 

 North Atlantic centers are not local, but are an expression of varia- 

 tions widespread in the earth's atmosphere. 



This conclusion is supported by an investigation of the curves of 

 consecutive twelve-months means. The natural question is now 

 whether these agreements occur in the shorter fluctuations from 

 month to month. We shall clarify our view of this matter by 

 investigation of the curves of figure 92 and figure 93. We see, for 

 example, that the monthly fluctuations in air pressure gradients in 

 the North Atlantic on the whole correspond to variations in the air 

 temperature in Norway, but fall generally a month later (see the 

 curves IV and V of fig. 92). The agreements are occasionally 

 almost complete though at times not so good. These apparent 

 disagreements of the relations may be actual or they may be attrib- 

 uted to errors in the air pressure differences, which are obtained 

 by very rough methods. 



We have already given the monthly variations of the temperature 

 in Stockholm, comparing them with the variations in the surface 

 temperature at the lighthouse stations along the Norwegian coast, 

 and we found a close agreement which extended even to the most 

 minute particulars. Since the variations in these regions agree 

 completely with the variations in the temperature of all Norway, 

 we must therefore conclude that fluctuations in air pressure gradi- 

 ents in the North Atlantic are accompanied by corresponding fluctua- 

 tions in the temperature of all Scandinavia and in the coast water 

 temperature of Norway. But the results of these fluctuations of 



