LOCOMOTION OF FISHES. 99 



Instant he rallies all his vigorous powers, 

 And faithful aid of every nerve implores ; 

 O'er battlements of cork up-darted flies, 

 And finds from air th' escape the sea denies. 



But the feats of fishes, in this way, are most re- 

 markable during their migrations, if any obstacles 

 are opposed to their determined progress. Under 

 these circumstances the little stickleback, the in- 

 habitant of almost every pond, river, and marsh, is 

 capable of bounding from the water, perpendicularly, 

 to a height of eighteen or twenty inches ; equal in 

 force to what would be required to project a man 

 into the air to a height of fifty or sixty feet. There 

 is no fish, however, the vaulting of which, in the 

 course of its migrations, is so celebrated as that of 

 the common salmon. It is very generally known 

 that, as the spawning-time approaches, these ani- 

 mals pass in shoals from the sea and ascend the 

 rivers; and, in their course, have frequently to 

 make their way over cataracts, the obstacles offered 

 by which would appear to be insurmountable. 

 Such are those of Pont Aberglastyn, among the 

 hills of Snowdoun, of Leixlip on the Tivy, in South 

 Wales, and of Kenneth, near Dublin; all which 

 the salmon every year surmount, and, having at- 

 tained the even water beyond them, quietly pursue 

 their march towards the sources of the river. There 

 are several of these falls which are celebrated as 

 salmon leaps, the fish having to make great exer- 

 tions to overcome their height, and making several 

 attempts before they can surmount them. The 



