HAL.—This is certainly possible: there is no doubt, that, in many successive generations, animals may 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. PHYS.—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 mixture of which with the moist warm air above the river this phenomenon is produced. I see some yellow flies beginning to come out; they have already felt the influence of the warm air: and look! a fish has just risen opposite that bank, and he rises again: let us prepare our tackle. POIET.—What flies shall we employ? HAL.—I recommend at least three; for the grayling lies deeper and is not so shy a fish as the trout; and, provided your link is fine, is not apt to be scared by the cast of flies on the water. The fineness of the link, and of the guts to which your flies are attached, is a most essential point, and the clearer the stream the finer should be the tackle. I have known good fishermen foiled by using a gut of ordinary thickness, though their fly was of the right size and colour. Very slender transparent gut of the colour of the water is one of the most important causes of success in grayling fishing. Let me see your book: I will select a fine stretcher. Now, for the lowest fly, use a yellow-bodied fly, with red hackle for legs, and landrail’s wing: for the second, a blue dun, with dun body; and for the highest, the claret coloured body, with blue wings; and let your first dropper fly be about three feet from the stretcher and from the other dropper, and let the hanging link which attaches them be 3½ inches long. PHYS.—There are several fish rising: I shall throw at that opposite—he appears large. HAL.—It is a trout and not a grayling. PHYS.—How do you know?