42 love's meinie. 



distinct relation between the shapes of birds and their 

 powers of flight. I suppose the form of the body is first 

 determined hj the general habits and food, and that 

 nature can make any form slie chooses volatile ; only one 

 point I think is always notable, that a complete master of 

 the art of flight must be short-necked, so that he turns 

 altogether, if he turns at all. You don't expect a swallow 

 to look round a corner befoi-e he goes round it ; he nmst 

 take his chance. The main point is, that he may be able 

 to stop himself, and turn, in a moment. 



47. The sto2)ping, on any terms, is difiicult enough to 

 ■understand ; nor less so, the original gaining of the pace. 

 We always think of flight as if the main difiiculty of it 

 were only in keeping up iu the air ; — but the bnoyancy is 

 conceivable enough, the far more wonderful matter is the 

 getting along. You find it hard work to row yourself at 

 anything like speed, though your impulse-stroke is given 

 in a heavy element, and your return-stroke in a light one. 

 But both in birds and fishes, the impelling sti'oke and its 

 return are in the same element ; and if, for the bird, that 

 medium yields easiW to its impulse, it secedes as easily 

 from the blow that gives it. And if you think what an 

 f effort you make to leap six feet, M'ith the earth for a 

 fulcrum, the dart either of a trout or a swallow, with no 

 j fulcrum but the water and air they penetrate, will seem to 

 ' you, I think, greatly marvellous. Yet of the mode in 

 whicli it is accomplished you Avill as yet find no un- 

 disputed account in any l)ook on natural history, and 



