SALMONID.E. 89 



the stream. For it is a well-known fact, that the Salmonida^ although 

 many of them are migratory at certain seasons, have their own haunts 

 and hunting grounds to which they steadily adhere, moving but a short 

 distance from one spot, in pursuit of their prey, and returning to it 

 when satisfied. 



Thus, in a mountain-brook, you shall find, perhaps, that the pool 

 between an upper and lower fall or rapid is occupied by two fish ; one 

 of these will lie at the head, the other at the tail, of the pool, the more 

 powerful fish selecting the spot which he chooses, and neither ex- 

 changing places, nor hunting far from his habitual haunts. 



In still waters, in like manner, you will find that, day after day, the 

 same large Trout will be seen under this bank, by that large stone, or 

 in the cavity formed by the roots of yon ash or alder ; and that he will 

 not stray to any distance from it, but will seek his prey nearly in the 

 same waters, and on the same side of the river, the opposite b.ank being 

 probably held by a rival fish. 



That this will at first be deemed far-fetched and improbable, I think 

 likely enough ; but the more we consider it, the more reasonable shall 

 it appear ; for when we weigh the great influence of light in the pro- 

 duction of colors, and then think how much the transmission of light 

 through different media, as, for instance, waters of different degrees of 

 density, purity, and color, affects the light itself, we shall find the 

 theory far less extravagant than it strikes us at a first glance. 



And here, I shall quote an anecdote, related in Salmonia, for the 

 purpose of elucidating an entirely different point, which yet is so much 

 to the purpose, in the present instance, that it is even more valuable 

 in illustration of this, than of that for which it is quoted. 



" A manufacturer of carmine," thus runs the story, " who was aware 

 of the superiority of the French color, went to Lyons for the purpose 

 of improving his process, and bargained with the most celebrated man- 

 ufacturer in that capital for the acquisition of his secret, for which he 

 was to pay a thousand pounds. He was shovvn all the processes, and 

 saw a beautiful color produced, yet he found not the least difference in 

 the French mode of fabrication and that which he had constantly 

 adopted. He appealed to the manufacturer, and insisted that he must 

 have concealed something. The manufacturer assured him that he 

 had not, and invited him to see the process a second time. He min- 

 7 



