36 THE WAY OF A TROUT WITH A FLY 



the similarly coloured feather from the next row being 

 useless. Other less well-known instances will be familiar 

 to North-Country fly-fishermen. Numerous instances could 

 no doubt be recounted where trout drew no such distinc- 

 tions, for their fastidiousness is much more marked on 

 some waters than on others. Indeed, I once fished a 

 tributary of the Test where my host told me the only fly 

 I need use, whatever might be on, was the Red Quill. It 

 was an August day, with a nice rise of pale watery duns, 

 but the trout took the Red Quill all day. Thank goodness, 

 the trout of my length of the Itchen know enough to keep 

 one guessing all the time. 



And now comes the time to consider the upward vision of 

 the trout. 



XI 



LOOKING UPWARD 



At this stage I should like to consider further the theory 

 put forward by writers well deserving of attention that the 

 colours of flies, natural or artificial, are not distinguishable 

 by the fish because the fly comes between the trout's eye 

 and the light. 



In order to do this effectively it will be well to get some 

 idea first of how things look to the human eye from under 

 water, not because the trout necessarily sees exactly in the 

 same way, but because it is the only way in which it is 

 possible for man to realize the lighting conditions of the 

 under-water world. The theory above mentioned is 

 generally supported by reference to the experiment of 

 placing a glass dish containing water in such a position that 

 lying on one's back one can look up through it at a floating 

 fly. In such a position no doubt the fly would be against 



