CHAP. xxv. Locomotion in Fishes. 357 



We may stay pleasurably for a moment to note a peculiarity in the 

 locomotion of fishes. It is based on principles markedly different 

 from those which govern the locomotion of birds and beasts. The 

 flight of birds is in the midst of a highly elastic element, the pro- 

 gression of beasts on the outside of an inelastic, immobile substance, 

 the swimming of fishes is conducted in the midst of an inelastic but 

 easily-displaced element. Again, the locomotion of both birds and 

 beasts is dependent on the law of gravitation, whereas fish may be 

 almost said to dispense with it, at any rate relatively to the element 

 in which they move. It is not so with a bird ; it could not move in 

 the air if its superior weight therein did not supply it with a fulcrum 

 whence to apply power, and with the means of utilising in some the 

 principle of the inclined plane. The fish, however, is suspended in 

 the midst of an element of very nearly the same weight as itself, so 

 nearly the same weight that the dilation or contraction of the little 

 air bladder, which most fishes possess, suffices to make it heavier or 

 lighter than water, and consequently to fall or rise quickly therein. 

 To solve the problem of locomotion in such widely different circum- 

 stances would have sorely puzzled man surely. Even with the secret 

 laid bare before him, and availed of in steamers, what a very poor 

 approach has he made to the rapidity of the motion of fish, a pro- 

 gression so rapid that the eye can scarcely follow the trout that has 

 darted up stream like a vanishing shadow. What is 16 or 20 odd 

 knots an hour to 160 or 200? And why should not the latter speed 

 be attained in vessels by following more closely the fish's method of 

 swimming, and utilising the unlimited powers of stored electricity. 

 Surely the " open secret " of the locomotion of birds and fishes may 

 serve, and be meant to serve, to show us how to utilise like powers, 

 and, with stored electricity as a motor, we may well vie with them 

 both in their own elements. 



To some this may seem grandly chimerical ; but to them we will 

 say that stranger things have happened ; such, for instance, as this 

 little book coming to a second and third edition ! With such extended 

 means of communication the widely scattered and divided Empire 

 of Britain could be consolidated into far the most powerful nation in 

 the world. But I beg pardon that a follower of " the contemplative 

 man's recreation" should have dared to be contemplative. Those 

 fishes set me on. 



