192 THE DIPPER. 



A concluding word on the remark, that " the 

 habit of the dipper walking underneath the water, 

 is too well known and authenticated to need any 

 additional information from me" [that is, from Mr. 

 Morris]. I am not a convert to the doctrine of a 

 subaquatic promenade : first, because I know that 

 the bodies of all birds float on the surface of the 

 water ; secondly, because I am convinced that birds 

 are obliged to make great exertions with their wings; 

 and feet in order to be able to reach the bottom 

 thirdly, because I am satisfied that, as soon as they 

 have arrived at the bottom of the water, the force 

 which enabled them to descend to it ceases to act. 

 Hence I infer that the body of a bird, impelled to 

 the bottom by the aid of the feet and wings, must 

 rise again when deprived of that aid. I can easily 

 conceive, however, that the dipper, by the use of 

 its legs and wings, may manage to keep sufficiently 

 near the bottom to be enabled to turn over the peb- 

 bles with its bill in quest of food ; because, in this 

 position, the legs and wings would have power to 

 act, and they would tend to counteract the rising 

 motion of the body. I maintain positively, that a 

 bird cannot, by any chance, walk on the ground 

 under water. The moment it attempted to do so, 

 the legs and wings, by the altered position of the 

 body, would be deprived of all depressing power ; 

 and the body itself would be raised up towards the 

 surface by the fluid in which it is immersed. This 

 would put an effectual stop to all proposed peram- 

 bulations at the bottom of the stream. This is only 

 theory, and theory may err. I often used to watch 



