178 SALMONIA. [SEVENTH DAY. 



be fitted to bear changes, which would have destroyed 

 their progenitors. It is said by Bloch, that graylings 

 are found in the Caspian sea, and in the Baltic, 

 masses of saline water ; though, as I have proved, the 

 grayling of England will not bear even a brackish 

 water without dying. And notwithstanding the 

 severity of the winter in high northern latitudes, 

 streams under the ice may retain a temperature not 

 much lower than some of the Alpine rivers. I have 

 seen grayling in Carniola, in a source at the hottest 

 season, not quite 50; and as, in large bodies of 

 water, the deepest part, in frost, is generally the 

 warmest, about 40, the degree at which water is 

 heaviest, I see no reason why grayling may not be 

 habituated to such a temperature coolness being 

 generally favourable to their existence. But see, the 

 fog which had filled the valley and hid the mountains 

 from our sight is clearing away, and I fear it will be 

 a hot day. Before the sun becomes too bright is 

 the best time for fishing, in such a day as this. As 

 soon as the fog is fairly off, the water-flies will begin 

 to appear, and fish to sport. 



PHTS. I see the fog has already disappeared from 

 the deep water in the meadow, where, I suppose, the 

 warmth of the air, from the considerable mass of the 

 water, is greater ; and which is further removed from 

 the hills sending down currents of cold air, from the 



