FOREWORD xi 



methods of the various schools. I would give much to be 

 able to leave behind me, when I pass over the ferry, a work 

 which would extricate the subject from the confusion in 

 which generations of inaccurate observation and loose 

 thinking and writing have involved it. 



It was an ambitious project, but that would not have 

 deterred me from the attempt; and I only gave up the 

 project when I reached the conclusion that there is one 

 governing factor in the treatment of the subject upon 

 which I know nothing, and upon which — so far as I can 

 learn — the scientific knowledge of my age is unable to help 

 me. I refer to the vision of the trout. As those who 

 penetrate beyond the opening pages of this volume will 

 discover, there are, in my opinion, reasons for suspecting 

 that the eyesight of the trout differs from that of man 

 in its appreciation both of form and of colour. In what 

 these differences consist, if they exist — and I do not pretend 

 that the evidence of their existence is conclusive — I am 

 entirely ignorant, and I see no means of lightening my 

 darkness any more than, as a being of three dimensions, 

 I see any prospect of appreciating the secrets of the fourth 

 dimension. If I could understand these differences, and if, 

 understanding them, I could put them into simple, lucid 

 English, comprehensible to fly dressers of every class, 

 then I could have given this generation a work on a subject 

 never yet comprehensively treated in any language, which 

 would at any rate have registered an advance in the art, 

 and would have done something to elevate it out of the 

 rut of convention, aggravated by empiricism, in which the 

 practitioners of the ages down to this have toiled. It was 

 not, however, to be, and I have arrived at a time of life 

 when I have little hope that the advance of science will 

 have solved the questions I would pose to it, while I still 

 have the energy to undertake such a work as I have in- 

 dicated. In these circumstances I have no wish to add yet 

 one more to those primers on trout-fly dressing, accepted 



