96 The American Salmon-fisherman. 



tiguous water with a mellow glow, yellower in color, and 

 by no means so pronounced and incisive as the flash of 

 the minnow. Mere inspection would, I believe, fail to 

 enable any one to determine the nature or form of the 

 object; but something was there softly luminous, and 

 endowed with motion and apparent life. Had it been 

 possible to view the fish through a thicker stratum of 

 water than that of the five feet which the tank contained, 

 I could not question that as its form became more and 

 more obscure, its resemblance to such flies would become 

 more and more marked. 



This experiment was repeated again and again under 

 the same, and different conditions of light and water. If 

 the investigation had any value at all, it demonstrated 

 that only when either from the size or color or distance 

 of the fly from the observer, its details were undistin- 

 guishable then, and then only was it possible for any- 

 thing with eyes to mistake the fly for a minnow.* 



* Since writing the above, shrimp were obtained and tried in the 

 same manner. 



The experiment was not altogether satisfactory, since I could not 

 get the shrimp to the tank alive. Though quite fresh, yet they 

 seemed to me more opaque and somewhat grayer in color than when 

 in life. That exactness of condition so desirable in an experiment 

 was therefore wanting. Still, I think the difference was hardly so 

 marked as to deprive the results of all value. 



It may be indeed I judged it probable that salmon may under 

 some conditions mistake some flies for shrimp, but it can only be 

 through a thicker or less transparent stratum of water than the five 

 feet of my tank. Under no circumstances could I detect more than 

 a suggestion of a resemblance. 



For the benefit of my English readers, should I be so fortunate as 

 to have any, I might say that the shrimp experimented with were 



