14 FLY-FISHING AND FLY- MAKING. 



more rapidly increasing refraction, but the distinctness 

 with which the object is seen increases in inverse pro- 

 portion. 



The bending or refraction which a pencil of light, 

 falling very obliquely on the surface of the water, under- 

 goes before arriving at the eye of a fish, is sufficient to 

 produce very great indistinctness and distortion of the 

 image of the man formed in his eye. 



Long before a pencil of light becomes horizontal, it 

 will not enter the water at all ; consequently, although 

 the fish may see the upper part of the man wading, he 

 will do so very indistinctly and in a new position, be- 

 cause the pencil will be very much refracted ; he will 

 not see the middle part of the man at all, because 

 the pencil does not enter the water, and he will see, 

 probably, his legs in the clear water, because there is 

 neither refraction nor obstruction to prevent him. So 

 that the figure of the man will be, in the eye of the fish, 

 cut in two portions, separated from each other by a long 

 unsubstantial interval. 



The lessons to be drawn from these theories are, 

 briefly, three. J st. A low bank on the level of the water 

 is a great advantage to the fisherman. 2d. The wader 

 has a great advantage over the bank fisher. 3d. It is of 

 great advantage to fish up stream, wading when the fish 

 are heading in that direction. " Observe," says Eon aid, 

 " that fish cannot see behind them ; all optics forbid it." 

 To which I add an emphatic endorsement. 



But the trout has, probably, in addition, another and 

 more subtle reason why my presence, or that of a waving 

 rod, is a signal for taking his leave standing not on the 



