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 
