The brisk sport enlivening that hour is so familiar that most of us have no thought of how astonishing it is. It comes when the atmosphere is still. Should it not, then, cause us to revise the understanding that in daytime we must have a breeze and a ripple if the trout are to come at the flies ? The accepted belief is that in a dead calm, especially if the sun is unclouded, the trout see the gut to which the flies are attached, become suspicious, and sink superior to the temptation ; and that when there is a ripple the gut is invisible and the flies are of natural aspect.

This belief is apparently so reasonable that it has never been openly questioned; yet, surely, there are considerations which shake it. First, there is the fact, just noted, that the trout come on with avidity during the placid evening hour. The light is not strong at that time; but it is very clear. To the human eye itself the gut in the water is visible : presumably, it cannot escape the notice of the trout, whose vision is acute. Besides, there is not much less light during the hour after sundown than there is during an hour in the middle of the day when the sky is covered by thick clouds. If the fish ignore the gut in the twilight, they should ignore it also during the dusk which sometimes falls while the sun is high; yet, whilst they rise freely in a calm at the one time, they do not rise at all in a calm at the other. It would appear, then, that the ripple is not in itself the condition of good sport during the daylight.

May it be that the ripple is only a symptom of the condition ? Can it be that the wind, which causes the ripple, causes also a state of the water in which the fish become lively and disposed to feed ? This suggestion may at first be flouted; but before discarding it anglers should take note that their craft, though of great antiquity, is one which has made extraordinarily little progress. The main principles of the sport have for centuries been accepted by generation after generation in unreflective acquiescence. This is so markedly the case that, although accustomed to speaking of trout in certain waters as " wary," or " cunning," or "sophisticated," we who wield the rod hardly ever suppose that the fish are subject to moods which are explicably referable to definite conditions.

If they will not rise on a day which seems in all respects perfect, we suppose they are sulking causelessly, and go home without further thought about the matter. That is treating the trout with scant respect. It is not the way in which we treat cattle, whose moods and attitudes are so definitely determined by atmospherical conditions that the skilled observer in the pastures can actually foretell the weather. We forget that, by the action of steam on the carbonates of lime and magnesia, carbonic - acid gas is constantly being generated under the surface of the earth ; that, although most of it escapes into the outer atmosphere, much of the enervating influence frequently rests in still waters; and that, therefore, far from being less in need of vitalising oxygen than the animals of the land and the air, the trout in many places are normally more in need. May it be that when they are not rising the fish are inert because the water is in want of freshening ?

The surmise that this may be so occurred to me on witnessing a suggestive incident on a Highland loch. Trout were needed to replenish a hatchery on the hillside. Each, as it was caught, was put into a pail of water, in which, ere long, there were half a dozen. By and by it was noticed that the fish were languishing. Some of them had turned upon their backs, and were to all appearance dying. The gamekeeper took the bailing pan; filled it with water from the lake; and, holding high his hand, plunged the water through the air into the pail. Within two minutes all the fish were as lively as ever. They had been revived by a fresh supply of oxygen.

Within the knowledge of most anglers there are certain undisputed phenomena supporting the theory to illustrate which I have described that interesting incident. Trout do not rise when a thunderstorm is impending. Why ? It cannot be because they are afraid of the stillness and the gloom : often they come on freely in the middle of a dark and silent night. May it not be that they remain down because, like the birds of the air, the beasts of the field, and mankind, fish are made sluggish by certain conditions of the atmosphere ? Soon after the storm has come, often when it is at the height of its rage and rattle, the trout rush at the flies as recklessly as any fisherman could desire. Of this, surely, the natural explanation is that they have been relieved of depression by the change which has been wrought in the atmosphere by lightning.

Even when there is no " thunder in the air," the angler, especially if he be on a lake, where causes and effects are more broadly manifest than they are on a river, will sometimes have experiences which point to the same conclusion. The calm of many a day is modified by puffs of wind; but if the trout do not rise in the hours of calm they do not rise in the minutes of ripple. The wind has not been sufficient to refresh the water and make their humour light. Sometimes, too, in a day of storm there are intervals of lull; and if the trout rise in the hours of ruffling they rise equally well when the lake is smooth. The refreshment of the water and the fish has not passed with the passing of the wind.

Still, it would be wrong to suppose that the character of the tackle is unimportant. It is beyond all doubt that fine gut is needed on still water. One cannot be absolutely certain that this is because the trout actually see the gut if it be not fine ; but it should be borne in mind that, apart from the question whether it is visible, thick gut has at least two objectionable qualities. It is less pliable than fine gut, and deprives the flies of the light and airy motions which they should have. It carries with it a shower of spray, which falls upon the water immediately after the flies and must tend to alarm the fish.

These are considerations deserving more heed than they usually receive. Most anglers take it for granted that fishing on a lake is coarse work compared with fishing on a stream. There seems to be some reason for that belief. A stream is narrow and not very deep, and as a rule any part of it can be reached by a fly as you walk along the bank; a lake is wide and deep, and even when one has fished a whole day there are great expanses unexplored. It is natural to feel that fishing on a lake is angling on a large scale, calling for less fragile appliances. In one respect this view is not altogether wrong. The flies that come out on lakes are in some cases larger than those which are common on rivers, and it is right to assume that the artificial flies for lakes must as a rule be larger than those which are proper on streams. In another respect, however, the view is wrong. On a stream the flies do not remain where they fall. They move down, and in moving beyond the radius of the shower of spray may float over, or by the side of, a feeding trout. On a lake, excepting in so far as they are moved by the angler, who as a rule should not move them at all, they do remain where they alight. On a lake, then, when the water is not ruffled by the wind, it is desirable that the gut should be as fine as is compatible with reasonable strength.

In the hope of making the gut invisible, it is often dyed. Some soak it in a solution of logwood ; some in ink; some in tea. All these expedients are rather worse than useless. This will be readily realised if you place a strand of dyed gut and a strand of gut undyed in a crystal bowl of water. The dyed gut will be conspicuous; the undyed, being opaque, will be almost invisible. If the bowl were black, or brown, or blue, or inky, the results would be the reverse; but it should not be forgotten that the colour of water looked through from below, as the trout look, is much more nearly the colour of unstained gut than that of any of the dyes.

For reasons which will be set forth in another chapter, the wind is less important on a river than it is on a lake. Here let it be mentioned that on the lake there can hardly, in one sense, be too much of it. Quite a gentle breeze, if continuous, is often sufficient to bring up the trout; but, if they are feeding in earnest, the wind will not put them down even though it rises into a gale. They will rush at a fly in the trough of a billow which leaves the bottom of the lake, at some shallow place, almost uncovered. The inspiriting nature of this discovery is mitigated only by the difficulties of fishing on a lake when the wind is very high. By way of providing against the emergency, some anglers take out with them a heavy stone fastened to a rope; the stone is to be dropped overboard when the boat begins to drift too quickly. This plan, which is better than not going out at all, has the disadvantage that a large fish may entangle the line round the rope, and break off. There is considerable reason for believing that the trout are often in the best of humours when the storm is at its highest; but the boat at that time is not easily controlled, and, indeed, is frequently blown ashore. Then the only resource is to go to the quarter of the lake from which the wind is coming, and cast into it from the bank. Sometimes the sport is as good as that which could be expected afloat if the boat were manageable.