Sense of Sight. 99 



know exactly what the sight of fishes is, but we must assume it 

 to be not much unlike our own, and we are not without grounds 

 for the assumption. By drawings on a blackboard. Dr. Hodg- 

 kinson showed how the eyes of both men and fishes were alike in 

 their main parts, the greatest divergence being that, whereas the 

 optic nerve in man occupies only a small portion "of the brain, in 

 fi^es it occupies pretty uearly the whole brain; and we may pre- 

 sume, therefore, that the sight of fishes is more sensitive. 



" Dr. Hodgkinson then dwelt with the phenomena of the pas- 

 sage of rays of light from the rare medium air to the dense me- 

 dium water, and the change in direction that the incident ray 

 undergoes; he pointed out the fact that under certain conditions 

 an angler on the bank might be invisible to u fish in the stream, 

 but the exultation of the gentlemen assembled was probably 

 damped when they heard that, in order practically to discover 

 the distance they must stand from the water in order to be invis- 

 ible, they must take their height and multiply it by fourteen, 

 which, as an unfortunate angler who was present pointed out, 

 would require him, seeing that he is six feet high, to stand eighty- 

 four feet from the water's edge before he could take advantage of 

 the invisible mantle Dr. Hodgkinson had promised him. The 

 case, however, is not quite so hopeless as this, for, as the doctor 

 pointed out, the water in which the fly-fisher angles is not gener- 

 ally so smooth as a mirror, and in ripple or broken water it is 

 impossible for fish to see the object on two legs that may be on 

 the bank. 



" In fishing for trout, wading in many streams is a, necessity, 

 and by means of an ingeniously constructed tank Dr. Hodgkinson 

 showed not only what the angler looked like to the fish when he 

 waded, but how his aspect was affected by the color of the bot- 

 tom of the river, and that of such cover as there might be on 

 the bank. The rather startling announcement was made and 

 demonstrated, that while the wader was duplicated so far as his 

 legs were concerned, another pair appearing upside down on the 

 actual legs, the man's body, if visible at all, was far away from 

 the legs, and overhead, where, if we put ourselves in the position 

 of the fishes, we should expect to see nothing but sky. No fish 

 then ever saw a wader with his two halves united, and whether 

 its feeble brain can ever connect together the two distinct objects 



