FOOD OF SALMON. 153 



rivers, might depend upon a sort of imper- 

 fect memory of their early food and habits ; 

 for flies form a great part of the food of the 

 salmon fry, which, for a month or two after 

 they are hatched, feed like young trouts — 

 and in March and April the spring flies are 

 their principal nourishment. In going back 

 to fresh water, they may perhaps have their 

 habits of feeding recalled to them, and 

 naturally search for their food at the sur- 

 face. 



Poiet. — This appears to me very pro- 

 bable. — But it is late, and we must return 

 and compare the crimped trout and salmon ; 

 and I hope we shall have another good day 

 to-morrow, for the clouds are red in the 

 west. 



Phys. — I have no doubt of it, for the red 

 has a tint of purple. 



Hal. — Do you know why this tint por- 

 tends fine weather? 



Phys. — The air when dry, I believe, re- 

 fracts more red, or heat-making, rays; and 

 as dry air is not perfectly transparent, they 

 are again reflected in the horizon. I have 



