THE SORT OF WATER GRAYLING LIKE. 337 



ling require water of a milder temperature than 

 trout do; water of the mean temperature of the 

 atmosphere. They do not thrive in mountainous 

 streams, and could never stem their rapid torrents 

 or surmount their natural obstacles as salmon do. 

 They cannot bound out of the water, and never 

 jump at a bait after the manner of trout. " The 

 grayling rises, however," says Mr, Ronalds, 

 " with great velocity, and almost perpendicularly 

 to seize his prey, at the top of the water, and 

 descends as quickly after making a summerset, 

 for the performance of which feat, the figure of 

 his body, and the great dorsal fin seem well 

 adapted." The following just remarks of Sir 

 Humphrey Davy .should be attended to by the 

 angler : "Besides temperature," he says, " Gray- 

 ling require a peculiar character in the disposition 

 of the water of rivers. They do not dwell, like 

 trout, in rapid shallow torrents ; nor, like char or 

 chub, in deep pools or lakes. They require a 

 combination of stream and pool ; they like a deep 

 and still pool for rest, and a rapid stream above, 

 and gradually declining shallow below, and a 

 bottom where marl and loam are mixed with 

 gravel; and they are not found abundant except 

 in rivers that have these characters." The largest 

 grayling I have ever caught I found in the some- 

 what deep, rapid, and smoothly running tails of 

 pools just before the formation of some rough 

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