XIX 



these points before drawing our final con- 

 clusions ; that observations conductefl within 

 restricted limits during only a few years do 

 not justify general conclusions and possess 

 mere local significance; that, considering the 

 fact that the phenomenon of migration is closely 

 connected with the course of the seasons 

 and covers zones, the phases of the pheno- 

 menon must be recognised over the whole 

 territory covered by the migration. And, finally, 

 seeing that the phenomenon of migration, in 

 both palaearctic and arctic regions, is closely 

 bound up with the course of the seasons, it 

 is inseparable from the conditions treated by 

 Newton's Law of Gravitation and Gauss's 

 Theory of the movement of heavenly bodies; 

 not to mention the fact that the axis of the 

 earth is oblique to its orbit or that we know 

 practically nothing about the life of our birds- 

 of-passage in the South, where, we must 

 presume, it is no „wonders", no „mysteries" 



but compelling circumstances, corresponding to 

 our autumn and winter, that bring about the 

 return. Consequently The „Ibis" fell short of 

 the mark in offering me the horizontally 

 „nearer Saxon" data, which are merely local 

 and unelaborated. 



The works of reference are as the follow- 



m 



The 



,Ibis" 



must not imagine that the 



above is merely a bibliographical catalogue. 

 It is a list of works of reference used by 

 the Hungarian Central Office for the collection 

 of data. Ever}' datum has been proved and 

 provided with the geographical co-ordinates etc. 

 This collection has been examined by many 

 illustrious ornitholo.gists, by Englishmen too 

 (among others by Dr. Dresser). We hope that 

 the „Ibis" will admit that we range far enough 

 beyond even the „nearer Saxony". 



Otto Herman. 



* See these sub IV p. XX. 



m* 



