THE SALMON. 151 



swollen by rains, although in the larger rivers 

 there may be said to be a limited daily rim. 

 When the fresh or flood has fairly mingled with, or 

 powerfully pervaded the estuaries, the run of fish 

 is often very great, more especially if there has 

 previously occurred a long continued course of dry 

 weather. In the latter state of matters (before the 

 fresh) these finny tribes will congregate at the 

 mouths of rivers, as if deterred from entering by 

 some principle of non-intrusion, and will not run the 

 risk of a Sunday slap, however harmoniously called 

 to do so by some powerful patron in the uplands. 

 They are then seen, and not unfrequently taken, in 

 vast numbers, but will not attempt to ascend, know- 

 ing either by the clearness of the intermingling river, 

 or by some instinctive feeling, that the supply of 

 water by no means equals the demand. But as the 

 fresh approaches, an increased activity may be per- 

 ceived among them, and mighty is then the waving 

 of powerful pectorals, and of broad-finned swinging 

 tails. This change is probably indicated instan- 

 taneously by the perceptive power of the nostrils, 

 and to this same sense may possibly be attributed 

 the singular fact of the greater proportion of salmon 

 returning to the very streams in which they had 

 their birth. As soon as the fresh water suffices for 

 their migratory purposes, they enter the river, and 

 advance rapidly so long as the flood continues, 

 seldom resting in their course while the water con- 

 tinues in any way discoloured. We have never 

 ourselves had any means of ascertaining the rate at 

 which salmon travel, but Sir William Jardine 



