This section is from the book "Salmon Fishing", by W. Earl Hodgson. Also available from Amazon: Salmon Fishing.
Why not put those questions to a test? Why not make a survey of the main rivers in the United Kingdom ?
I have done so. The results will be found in chapters immediately following. The information set forth, it will be noticed, is in all cases given on authorities that are unquestionable. In another chapter, on Storage and Passes, I will discuss the chief fact brought out in our survey of the rivers. My endeavour will be to show that all the troubles disclosed are ultimately due to a single condition, the want of a natural, equable flow; and that for this condition a remedy has been found. Meanwhile I may perhaps venture a belief that salmon fishing is now, as grouse shooting seems to have been fifty years ago, a sport only beginning to be scientifically understood and systematically cultivated.
 
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