ON RAPID STREAMS. 19 



salmon up, which the structure of the weirs at 

 present existing prevents. Second. When the 

 salmon has gone up, to preserve them till they 

 have spawned ; this would be necessary in great 

 extent till a stock natural to the waters were bred. 

 Third. To let the fry and old fish back again, 

 which the weirs also in a great measure prevent. 

 The great obstacle to the salmon is the forbidding- 

 structure of the weirs ; these might readily be so 

 altered as to answer every useful purpose as re- 

 gards the turning off of the water, whilst at the 

 same time to permit salmon to get up and pass 

 back again. The landowners are indeed short- 

 sighted when they can only recognize the value of 

 water to their land, and not comprehend the im- 

 portance of salmon in their rivers. I have gone 

 astray, I know, from my subject ; my inclinations 

 would almost induce me to write a chapter on the 

 subject of preserving the salmon and trout, but 

 it is irrelevant to the purpose of this undertaking 

 and I must forbear, at any rate for the present ; 

 I may be tempted perhaps hereafter to send home 

 some remarks on the subject, but I now hasten 

 back to the trout. 



The majority of trout then in rapid streams are 

 by a natural necessity impelled to be constantly 

 feeding. Now doubtless, the stomach of the trout, 

 like the stomach of other animals, requires change 

 of food ; it is demanded by the body and suggested 

 by the appetite. All the requisite constituents of 

 the trout's body could not probably be found iu 

 any one particular kind of food, or such food could 

 c 2 



