288 FACULTIES OF BIRDS. 



rest and breed upon, and th6se are therefore com- 

 monly called Gulrocks. Now if there be such glob- 

 ules (or ethereal islands), they must be supposed of 

 such magnitude only, and set off at such distance 

 as their reflective light may not reach home to our 

 earth (though perhaps they may serve to illuminate 

 our atmosphere), else they would ere now have 

 been discovered, and yet no farther off than these 

 birds may conveniently arrive unto them in such 

 time as may be most convenient to allow them. 

 This I do suggest, because it is as hard for me to 

 persuade myself that they come from any other part 

 of this earth as it is to persuade another that they 

 come from the moon ; and, therefore, if the moon 

 will not be allowed, some other place must be found 

 out for them."* 



This notion, extravagant as it appears to be, was 

 discussed by the celebrated Ray and his correspond- 

 ents ; but, as might have been expected, it was de- 

 cided by them that the moon is too far off to be 

 reached by our migratory birds. 



Dismissing these untenable conjectures, we shall 

 now state a few facts proving the migration of birds 

 to other countries. 



In the Philosophical Transactions,! Catesby, who 

 gave much attention to this subject, remarks, that, 

 besides the migratory birds which remain and breed 

 throughout the summer, there are others which ar- 

 rive periodically at certain places, for the sake of 

 some sort of grain or other food of which their own 

 country may be supposed destitute. These birds, 

 after a short stay, depart, and are not again seen 

 until that time twelvemonth, at which time they re- 

 turn, and continue repeating their annual visits. 

 Pursuing the subject, the same sensible naturalist, 



* An Essay towards the probable Solution of this Question, 

 Whence come the Stork, &c. ; or where those Birds do proba- 

 bly make their Recess, &c., 12mo., Crouch, London, 1703. 



t Vol. xliv., part i., for the year 1746. 



