48o THE PHILOSOPHY 



driipeds, there are many fpecies who lie in a dormant or torpid ftate 

 during winter. But, if the fwallow be excepted, not a fingle fpecies 

 of birds, notwithftanding the great numbers which, at ftated times, 

 appear and difappear in every corner of the globe, has ever been dif- 

 covered in that ftate. This circumftance alone, though we cannot 

 yet afcertain the precife places to which different fpecies of birds of 

 paflage refort, is a moft convincing proof of migration in general. 



It has been afferted, and even believed, by fome naturalifts, that 

 fwallows pafs the winter immerfed under the ice, at the bottom of 

 lakes, or beneath the waters of the fea. Olaus Magnus, Archbifhop 

 of Upfal, feems to have been the firft who adopted this opinion. He 

 informs us, that fwallows are found in great clufters at the bottoms 

 of the northern lakes, with mouth to mouth, wing to wing, foot to- 

 foot, and that in autumn they creep down the reeds to their fubter- 

 raneous retreats *. ' That the good Archbifhop,' Mr Pennant arch- 

 ly remarks, ' did not want credulity in other inftances, appears from 

 * this, that, after having ftocked the bottoms of the lakes with birds, 

 ' he ftores the clouds with mice, which fometimes fall in plentiful 

 ' ftiowers on Norway and the neighbouring countries!' Klein has 

 endeavoured to fupport the notion that fwallows lie under water du- 

 ring the winter, and gives the following account of their manner of 

 retiring, which he colleded from fome countrymen; They afferted, 

 he tells us, that the fwallows fometimes affembled in numbers on a 

 reed till it broke and funk them to the bottom : That their immer- 

 fion was preceded by a kind of dirge, which laftedmore than a 

 quarter of an hour : That others united, laid hold of a ftraw with 

 their bills, and plunged down in fociety : That others, by clinging 

 together wuh their feet, formed a large mafs, and in this manner 

 committed themfelves to the deep f. 



Two 



* Derham's Phyf.-Theol, pag. 349. 



t Klein Prod. Hift. Avium, pag. 205.— 206. 



