70 THE SCIENCE OF DRY FLY FISHING. 



in which to fish, I think I should choose the hours between 

 10 a.m. and 2 p.m. 



The cause which leads to the " rise," speaking of this 

 rise as that mysterious impulse which suddenly quickens 

 the trout world into the activity of feeding time, has, so 

 far as I am aware, never been satisfactorily explained ; it 

 is, therefore, with some diffidence that I advance a theory 

 which I have held for some time as to this important 

 problem. 



I consider that one common cause of the " rise " is the 

 sudden impulse of the pupae of the Ephemeridae to ascend to 

 the surface and take wing. 



Fishing one day in the Axe with the Grannom 

 Fly, I had by noon creeled several trout, when a furious rise 

 of the fish commenced in my neighbourhood. 



To my surprise neither the rising trout nor dace would 

 look at the Grannom, and after many fruitless casts I decided 

 to change my fly. This I did several times, but with no success 

 until I at last noticed a small fly on the water. 



By the aid of my small butterfly net I captured the fly, 

 which turned out to be an Iron Blue in its sub-imago state, 

 and the first I had seen that season. Hastily putting one 

 on my cast, I was into a fish my first throw, and although 

 the rise only lasted some twenty minutes longer I got 

 seven other good fish. When the rise ceased there existed 

 a big hatch of Iron Blue in the air, but the few solitary 

 rising fish took no further notice of the Iron Blue Duns, which 



