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performed in the old undeviating westerly direction, until dawn 

 finds them at their goal on the shores of England ; neither tired 

 nor hungry after their great exertions. 



This programme may not be carried out in its entirety by all 

 species, but to the writer it forms a true sketch of migration 

 under normal conditions, according to the theories of the author. 



Von Middendorff's theory of a " sense of direction " possessed 

 by birds, has already been discussed. There remains, of those 

 mentioned by Herr Gatke, that of Professor Palmen. The latter 

 ornithologist, after selecting certain well-known species, carefully 

 accquired all the information he could obtain from the notes of 

 travellers and local investigators relating to their progress across 

 the Eastern Hemisphere. He then mapped out what he considers 

 are the chief routes these particular species follow during their 

 journeys. In all cases the latter traverse sea coasts or great river 

 valleys, from which fact the Professor argues that these natural 

 routes are followed by migrants as guides to their destination. In 

 referring to this theory, Professor Newton, in his "Dictionary of 

 Birds," remarks : " One of the routes (X) [i.e. starting from 

 Greenland and Iceland, passes by the Faroes to the British 

 Islands and so joining the second (B) and third (C) runs down 

 the French Coast] , described by Professor Palmen, and one of 

 considerable interest to dwellers in the United Kingdom, is 

 extremely questionable. Indeed, the data to establish its 

 existence were not forthcoming when he wrote, and probably 

 are not forthcoming now, though in the interim much has been 

 done toward the collection of facts at light-houses and light-ships 

 around our coasts by the * Migration Committee ' appointed by 

 the British Association in 1880." It is, therefore, very interesting 

 to find that Mr. Eagle Clarke, who approached the subject without 

 any preconceived theories or bias, confirms Professor Palmen's 

 statement, in his digest of the information collected by the above 

 Committee. 



Herr Gatke, however, does not even enter into a detailed 

 criticism of these theoretical routes. In alluding to them he 

 remarks : " Observations in nature on the author's own part 

 appear not to have been made the basis for this work," which is 

 as much as to say, that observations, unless personally con- 



