SIGHT OF TROUT 93 



the vibration of the air or other elements, but similar 

 vibrations of these elements can be produced without 

 sound, and the trout may, therefore, depend on the 

 tactile nerves rather than on the auditory ones. If 

 trout were capable of hearing, I do not think that 

 wading would be so productive of good results as it 

 undoubtedly is. The noise of one's brogues on the 

 pebbles can be distinguished when the ear is sub- 

 merged for considerably over half a mile in perfectly 

 quiet water in rivers, and for miles in lakes. 



THE VISION OF A TROUT 



Although it is supposed that trout cannot see an 

 object which is situated directly behind them that 

 is, in the direction of their tails the angle at which 

 their sight is limited behind each shoulder has, so far 

 as I am aware, never been discussed. 



It can be assumed that this limit of sight is a variable 

 one, depending on physiological characteristics, and 

 also varying at different periods, according to the 

 seasonal changes and the age and condition of each 

 fish. 



From my own observation of trout I consider that, 

 if the eyes are assumed to be the centre of the hori- 

 zontal plane in which the fish is lying, it can see 

 in that plane from a point right ahead to an angle of 

 about 60 degrees behind each shoulder. In other 

 words, that any object situated in the 300 degrees of 

 the forward part of the horizontal circle surrounding 



