LOOKING UPWARD IN DUSK AND DARK 47 



ness of detail with which I saw it looking down upon it in 

 the open. Later on, in a corner of the Itchen in the shelter 

 of a boathouse and a bank, I placed the mirror under some 

 natural red spinners and pale watery duns floating spent 

 upon the surface, and again every detail was as clear from 

 below as it was to me looking down upon the flies from 

 above. This test may have been vitiated by the fact that 

 it was carried out under the open sky, so that the little 

 mirror may have reflected upon the flies the light which 

 made the detail clear. At any rate, up to this point I 

 have seen nothing to prove that the trout looking up at 

 the floating fly, natural or artificial, sees it in silhouette 

 without colour (except, perhaps, when the fly is directly 

 between him and a strong light), and much to lead me to 

 think that he probably sees it, according to his capacity 

 for appreciating colour, as clearly from below as man 

 does from above. I consulted Dr. Francis Ward, the 

 author of " Marvels of Fish Life," upon the subject, and 

 he suggested the use of a trench periscope so boxed in as 

 to exclude all possibility of the mirror reflecting back 

 upon the underside of the fly the light of the sky, but up to 

 the present I have not been able to give the scheme the 

 necessary attention. 



There is, however, the indisputable fact that the trout, 

 which at dusk, in the absence of moonlight, is unable to 

 distinguish the angler casting a short line close behind 

 him, is able to make fine distinctions of pattern in the flies 

 presented to him, and that fact suggests to me that the 

 under-water region is better lighted for his vision than 

 the air above. 



