CONTENTS, XI 



CHAPTER XI. 



Page 



FLIGHT OF BIRDS . .231 



Flying similar to swimming ..... 231 

 Swimming-bladder of fishes . . . . 232 



Air-cells of birds discovered by Harvey . . . 233 

 Air-bones, according to Blumenbach . . . 233 



Experiments of Montagu ..... 235 

 Mechanism in the Pelican ..... 236 



Remarks of Sir Charles Bell 238 



\Vings and tail, as organs of flight .... 241 

 Commencement of flight . . . . . 242 



Artificial wings 243 



Muscles of flight 244 



CHAPTER XII. 



MIGRATION OP BIRDS . 248 



Migration twofoldnorthward and southward . . 248 

 Birds which return from southern climes in the spring 249 

 Island of Berneray in the breeding season . . 250 



Departure of birds in autumn .... 252 



Conjectures respecting the appearance and disappear- 

 ance of birds ....... 253 



Account of Swallows found on the banks of the Rhine . 255 

 White's investigations as to the appearance and disap- 

 pearance of birds ...... 256 



Opinion of Mr. Bree on the same subject ... 257 

 Swallows kept in winter ..... 259 



Examination of the sand-banks at Waverly . . 261 

 Submersion of Swallows ..... 262 



Submersion of Swallows believed in by Linn.'cus, Klein, 

 Cuvier, and others ...... 263 



Anatomical argument against submersion . . . 265 

 Migration to the moon ...... 266 



CHAPTER XIII. 



MIGRATION (continued) . . . . . . . 268 



Facts proving the migration of birds to other countries 268 



Catesby's observations on the migration of birds. . 269 



