REMARKS 
ON 
THE DIVING OF AQUATIC BIRDS. 
—< 
“Tux superior velocity with which Aquatic Birds 
swim under water has not wholly escaped notice ; 
but it is not entirely produced by the action of the 
wings, which are sometimes used as fins to accelerate 
the motion, but is occasioned by the pressure of the 
water above. In swimming on the surface a bird 
has two motions (one upwards, the other forward) 
at every stroke of the feet; so that, when covered 
with water, that force which was lost by the up- 
ward motion is all directed to the progressive, by 
which it is enabled to pursue its prey or to escape 
an enemy with incredible speed.” 
Many years since, when perusing, for the first 
time, the foregoing observations on the diving of 
Water-fowl, contained in the Introduction to Mon- 
tagu’s ‘ Ornithological Dictionary, ’pp. xxxix & xl, the 
insufficiency of the author’s attempt to solve this 
