132 THE BIRDS OF HELIGOLAND 



planets in their courses. For centuries this question has received 

 the most serious consideration on the part of inquirers, but no final 

 solution of the problem has as yet been arrived at. Nor, indeed, 

 is it likely that such will ever be the case, since the performances 

 of birds during their migrations are raised entirely beyond the range 

 of man's mental and intellectual faculties. 



In their perplexity to account for this remarkable phenomenon, 

 scientists and observers sought refuge in the assumption of an 

 ' Instinctive Action ' on the part of birds, in virtue of which they 

 adopted unconsciously the right road towards the attainment 

 of an unknown goal. Even such unexcelled observers of the life 

 and actions of birds as Naurnann and the elder Brehm, in the 

 course of observations more numerous and searching than any ever 

 comprised within the 'span of a man's life, yet got no further than 

 to the assumption of this said instinctive action on the part of 

 birds. Later observers, to be sure, have rejected with contempt 

 this explanation of a problem unsolved at the present day, but all 

 attempts at an explanation which have hitherto been made have 

 left it in exactly the same position in which it stood centuries ago. 

 The winged traveller, speeding on his way during the darkness of 

 night, in unerring course over vast expanses of ocean, presents to 

 the savants of our day as great a riddle as it did to the first observer 

 in ages before the dawn of history. 



Alfred Newton, in his excellent article on ' Birds ' in the Ency- 

 clopaedia Britannica, rejects the idea of instinct as a mere evasion 

 of the difficulty of the question, and as excluding all scientific 

 investigation of the same. Nevertheless, he says we ought to grant 

 that inherited, but unconscious, experience which, indeed, was all 

 that was understood by instinct certainly formed a factor in the 

 migratory process. According to this view, birds after all acted un- 

 consciously in a manner suited to a certain purpose ; this, however, 

 in the usual way of speaking, can still only be described as instinctive. 



But can experience be something of which the subject is 

 altogether unconscious ? and, further, can experience, the result of 

 which is positive knowledge, be actually inherited ? 



Dr. von Middendorff, whose Siberian voyages of investigation 

 extended to the northern parts of the Taimur Peninsula and who 

 has also made most serious efforts towards solving the problem of 

 bird-migration assumes that there is inherent in birds ' an inner 

 magnetic sense ' which guides them on their wonderful migrations 

 (Die Isepiptesen Russland, p. 9). He believed he had discovered 

 that the routes of the spring migrations of Asiatic birds converged 

 towards the Taimur Peninsula, in which region one of the magnetic 

 poles is situated, and this led him to adopt the above hypothesis. 



