410 



THE POPULAR SCIENCE MONTHLY 



during the intervals of migrations ; and the Kjulen range was prob- 

 ably selected as their habitat, not because it was proved to be so, but 

 because so little is known about it at all. The answer to the second 

 question is certain : They go to the sea. Those on the east of tlie 

 backbone of Norway go to the Gulf of Bothnia, and those on the west 

 to the Atlantic Ocean (Fig. 4), and out of eighteen migrations which 

 have been investigated, one only, and that very doubtful, is reported 



Fig. 4. Ot'TLTNE Map of Scaxdin'avia. TIip two main valleyB. Giulbraixlsdalon riid tlie valley 

 of the Glommen, run nearly iioitli and Boulh. The course of the Lemmiugg crosses tbLbe at 

 right angles, as indicated by the arrows. 



to have been directed southward. The question as to the cause of 

 these migrations remains, and is a very difficult one to answer. "We 

 have been told that the foreknowledge of approaching scAcre weather 

 predetermines the exodus : my experience, however, contradicts this, 

 and it may be dismissed as merely a popular superstition. Unusual 

 reproduction and consequent deficiency of food is a more plausible 

 theory ; but I have always noticed that, just as with the swallow, a 



