86 THE SCIENCE OF DRY FLY FISHING. 



much behind the fish as is possible. Wading, again, for 

 this reason will be the most advantageous position for the 

 fly fisherman. 



It may be argued that the appearance of the waders 

 below the surface, when within the zone ol the lateral vision 

 of the trout (see the unshaded portion of Diagram 7} 

 will scare the fish more than the appearance of the fisher- 

 man above the water. This is not so, however, for the 

 rays of light from the fisherman on the bank, say at 

 forty feet distance, would lose nothing in passing through 

 the air until they strike and enter the water (as at b B 

 Diagram 9) ; they will then only have some three to six 

 feet of water to pass through before reaching the fish. A 

 certain amount of light will be undoubtedly lost, even in 

 this small distance, owing to the density of the water, 

 but the vertical depth of the fish below the surface of any 

 trout stream will never be sufficiently great to prevent all 

 rays reaching it. This density of the water will cause a very 

 rapid diminution of the rays from any sub-aqueous object, 

 as horizontal or vertical distance is attained ; and while 

 objects may, under favourable circumstances, be still visible 

 to the fish twenty-five feet away in any horizontal direction 

 within the zone of its horizontal light, they may in calm, 

 still waters be taken as being unnoticeable under ordinary 

 circumstances at a distance of about thirty feet. In rapid 

 running water the rays from any object will be still further 

 lost or deflected by the eddies, etc. 



