[ *43 ] 



Thefe birds therefore fhould, according to the hypothecs of 

 migration, have been paffing to the more Southern parts of Afia, 

 but I do not find it obferved by any Afiatic traveller that they have 

 the fame fpecies of hirundines with us, or that they are only feen 

 in thofe parts during our winter. 



Between what hath been advanced in the preceding and prefent 

 diflertations, the arguments againft the periodical migration of 

 fvvallovvs have filled many pages, and it may be right to bring 

 them to a conclufion, by anfwering an objection which is much 

 relied upon by thofe who maintain the contrary opinion. 



It is frequently allied by thefe, where and when the fwallow 

 moults, if this does not happen in parts of the globe to the South- 

 ward of Europe. 



To this I do not pretend to anfwer by informing them where or 

 when thefe birds change their feathers ; but I may equally afk 

 the queftion with regard to nine of the birds out of ten which 

 have been defcribed by naturalifts, becaufe we are entirely un- 

 informed about this matter, except in relation to thofe which 

 we ufually eat, or keep in cages. 



It is true, that moid, if not all of thefe, commonly moult with 

 great regularity ; but it is alfo known that there are often excep- 

 tions to every general obfervation or rule ; nor do I fee why it is 

 more neceflary that every bird mould moult, than that every fifh 

 fhould not have wings, which would have been moft confidently 

 maintained by the old naturalifls who were unacquainted with 

 the flying fifh. 



Again, it is part of the known definition of a bird to be an 

 animal covered with feathers, and yet thofe of the Caffowary and 

 the Silky fowl of the Eaft Indies rather referable hairs than plu- 

 mage ; and this is the cafe fo ftrongly with the latter, that it hath 



I i 2 given 



