THE SALMON. 189 



difficulties with which they have to contend, they are 

 said to ascend the Rhine and the Aar, pass through 

 the Lake of Zurich, and find those places in the shal- 

 lows of the Limmat, among the secluded valleys of 

 the central Alps, in which they were at first produced. 

 In like manner, the salmon of North America ascend 

 the long rivers of that country, pass through the lakes, 

 and find their way to their native streams, with the 

 most persevering industry and the most unerring cer- 

 tainty. 



In their progress, they always have their heads to 

 the stream ; and their muscular power must be very 

 great, as they shoot up the rapids with the velocity of 

 arrows. They are sensitive and delicate in the extreme ; 

 and equally avoid water that is turbid or tainted, and 

 that which is dark with woods or any other shade. 

 They serve as a sort of weather-glasses ; as they leap 

 and sport above the surface before rain or wind ; but 

 during violent weather, especially if it be thunder, 

 they keep close to the bottom ; and they either hear 

 better than many other species of fish, or they are 

 more sensitive to those concussions of the air produced 

 by sound, as any loud noise on the bank throws them 

 into a state of agitation. When their progress is 

 interrupted by a cascade, they make wonderful efforts 

 to surmount it by leaping ; and as they continue to do 

 that at places which a salmon has never been known to 

 ascend, their instinct cannot be to go to the particular 

 spot where they were spawned, but simply to some 

 small and shallow stream. 



Many " salmon-leaps " are celebrated, in those parts 

 of the country where there are cascades upon the clear 



