A DAY ON THE ITCHEN 79 



self in his actual environment, a difficult task 

 at all times, even when he is a human being 

 whose upbringing as a soldier or a seaman has 

 followed much the same lines as your own. 

 You may have met him. A precis of his bio- 

 graphy may lie before you, and doubtless, if 

 you are wise, you have tried to master his 

 national characteristics in the pages of history 

 or diplomacy. An even more difficult task 

 lies before you when your opponent is not a 

 human being but a trout, living in another 

 element, with all the difference in the world 

 between its optical phenomena and those obtain- 

 ing in the atmosphere in which you live. Dr. 

 Ward, by his experiments in under-water photo- 

 graphy, has done good service to fly-fishers, 

 both wet and dry. His photographs teach the 

 wet- fly man the importance of paying atten- 

 tion to the direction of the source of light which 

 illuminates the fly as it approaches the fish, 

 the "flash," as he calls it. For the dry-fly 

 man he has done more. He has shown the 

 limits, in still water, of what he calls the 

 " window " on the surface, through which a 

 trout sees objects in the air above the stream 

 or its banks. He has proved that, beyond the 

 " window," the underside of the water-surface 

 appears to the trout as a looking-glass, which 



