32 SMITHSONIAN MISCELLANP:OUS COLLECTIONS VOL. yo 



surface of the Atlantic Ocean could be attributed to variations 

 in the Labrador current water-masses, but not to the ice whose 

 influence he considered purely local. 



In his well-known investigations on the action centers of the 

 atmosphere H. Hildebrand Hildebrandsson (1897 to 1899) con- 

 siders the influence of ocean currents upon the climate. He shows 

 that the precipitation in winter at Thorshavn has the same char- 

 acter as the precipitation of the previous summer in St. Johns, 

 Newfoundland, and also of the following summer in Berlin. He 

 suggests that a mild and moist winter in northwest Europe may 

 be produced by strong development of the barometric minimum 

 between Iceland and Norway. A continuous air current from 

 the southwest would then flow along the Gulf Stream. Such 

 southwest winds would increase the velocity of this stream and 

 thereby in all probability the temperature of the ocean surface 

 v/ould be raised. 



If these things are so, says Hildebrandsson, it is apparent that 

 if the winter precipitation in Thorshavn governs the precipitation 

 of the following summer in Berlin, the precipitation of the pre- 

 vious spring and summer in Newfoundland would govern the preci- 

 pitation at Thorshavn. Newfoundland lies not in the Gulf Stream 

 but in the cold Labrador Stream. It may therefore be maintained 

 that an increase of the Labrador Stream would tend to cool the 

 Gulf Stream and that this cooling would be shown half a year 

 later at Thorshavn. In this way the successive changes of preci- 

 pitation found may be explained by variations of the North Atlantic 

 Ocean currents. 



At the same time, however, Hildebrandsson shows that for an 

 interval of fifteen years a distinct correspondence persisted between 

 the precipitation in winter in British Columbia on the Pacific coasts, 

 and the rainfall of the following autumn in the Azores. In this 

 case it seems to be shut out of the argument that the correspon- 

 dence of the precipitation should be governed by ocean currents. 



Hildebrandsson considers that it is yet too early to assign the 

 causes of these phenomena. It can only be said with certainty that 

 some action takes place between the atmosphere and the surfaces 

 of the ocean and the continents so that a disturbance which occurs 

 at one place produces noticeable effects very far away. The cause 

 of a phenomenon must often be sought at great distances, even 

 in the other hemisphere. It may be possible that it is not a simple 

 accidental affair when long periods of drought occur in Europe in 



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