OF NATURAL HISTORY. 479 



firft and moft probable is, that they remove from climate to climate 

 at thofe particular feafons when winged infedts, their natural food, 

 fails in one country or diftrid and abounds in another, where they 

 likewife find a temperature of air better fuited to their conftitutions. 

 In fupport of this opinion, we have the teftimony, as formerly men- 

 tioned, of Sir Charles Wager, of M. Adanfon, and of many naviga- 

 tors. It is equally true, however, that fome fpecies of fwallows have 

 been occafionally found in a torpid ftate during winter. Mr Col- 

 linfon gives the evidence of three gentlemen who were eye-witnef- 

 fes to a number of fand-martins being drawn out of a cliff on the 

 Rhine in the month of March 1762 *. The Hon. Daines Barring- 

 ton, in the year 1768, communicated to Mr Pennant, on the autho- 

 rity of the late Lord Belhaven, the following fadt : ' That numbers 



* of fwallows have been found in old dry walls, and in fand-hills, 



* near his Lordlhip's feat in Eaft Lothian ; not once only, but from 



* year to year ; and that, when they were expofed to the warmth of 

 ' a fire, they revived f*' Thefe, and other fads of the fame kind, 

 feem to be uncontrovertible; and Mr Pennant infers from them, that 

 ' we muft divide our belief relating to thefe two fo different opi- 

 ' nions, and conclude, that one part of the fwallow tribe migrate, 

 ' and that others have their winter-quarters near home f .' But we 

 fhould rather incline to think, with thofe naturalifts who fuppofe 

 that the torpid fwallows which are occafionally, though very rarely, 

 ^ifcovered in the winter feafon, have been obliged to remain behind, 

 becaufe they were too young, weak, difeafed, or fuperannuated, to 

 undertake a long and fatiguing flight. Still, however, that the tor- 

 pidity of the feathered tribes fhould be folely confined to the fwal- 

 lows, is a very fingular fad in the hiftory of Nature. Among qua- 

 drupeds, 



* Philofoph. Tranfaa. vol. 53. pag. loi. art. 24. 



t Pennant's Britifli Zoology, vol. 2. pag. 250. 8vo edit. 



i Ibid. 251. 



