There is a general objection to almost all of the theories mentioned. It is that they are based on a strangely unscientific understanding of the nature of light. Take the lanes-of-light notion. It was first stated to me on Clatto, a lake in Fife, by P- P-A-, a man of exceptional intellect whose attainments in sport and in the criticism of literature are a tradition held in respect and affection at the Universities of St. Andrews and Edinburgh. "We shan't get many to-day," he remarked, when we had been on the water, without a rise, for nearly an hour. "No?" "I fear not," he said quietly: " I never knew them rising well when there were lanes of light." With a slow wave of his left hand, he indicated the offending glimmer. Was it possible that this eminent thinker, P. P. A., actually supposed that the light was distributed in lanes ? The surmise was disquieting, and I ventured to remark that there was not really any lane of light: the light was all over the water, though only a section of it was seen by us : the same illusion would be always produced by the sun, or the moon, or a solitary star, if the boat happened to be drifting towards the source of light: if it were drifting any other way, there would be no visible " lane of light" at all. Incredible as it seems, my surmise was not unfounded. My distinguished friend had not been consciously using a figure of speech when he noted the "lanes of light." After a moment's reflection, he said, " Ah! Just so. I thought it was the local reflection of that little break in the clouds near where the sun is; but I see it must be the same all over the loch".
This disturbing talk seemed to warrant a spirit of inquiry into other assumptions about the light in angling. Not long afterwards I was with another man on the same lake. It was morning; the wind was from the east, which, as Fife is on the east coast, was not a bad portent; we had just begun our first drift. " What do you think of the water ?" I asked. "Splendid," he answered, gaily. "Rough and blue ; no glare ; the very water I like to see!" "Yes? Look round, then." He turned ; and saw that all the broad expanse behind was sparkling as if it had been studded with diamonds. "What if the wind changed, and we had to cast in that direction ?" " O," said my companion ruefully, " it would never do at all: not a fish would stir !" " Well, it's all the same where you throw the flies. The glare's in front as well as behind. Don't you perceive ?" He perceived ; but the truth had never before occurred to him.
Only part of the truth, however, was revealed in those conversations. The question to be considered is much less how the phenomena of light impress the angler than how they impress the fish.
From the nature of things, a complete solution of this problem is impossible. Even if we could lie under the water and look upwards, we could have no assurance that our vision of things would be identical with that of a trout. The trout would detect objects that escaped us, and those which were visible to both would be seen differently. The trout could tell a dun-winged fly with a claret body from a dun-winged fly with a red body; but to the human eye such flies would be much alike from three feet under the surface.
Still, there is a respect in which, looking upwards into the air, the trout and the human observer would be at one ; and this unity is of great importance in relation to the general assumption that what the sportsman sees on the water from above the trout sees from below. To a fish or a man looking straight up at noon from a stream or a lake on the equator, there would be a glare; but it would be the direct glare of the sun itself, not the reflection of its light. In a water of our own latitudes the sun would disturb the vision only when trout or man had cause to look aslant towards some southern quarter. The disturbance might put the man off rising if there were something in the glare which it would be good to snatch ; but it does not seem reasonable to suppose that it would keep down the trout. On the contrary, it should bring him up. Even if a trout can look at the sun as an eagle is said to do, the extreme dazzle of the light must surely blur the shape and colours of a fly ; and if the fish thinks that some object between its eyes and the sun is a desirable insect, surely he must rush at it more rashly than he would rise at a fly floating in a light permitting of critical inspection ? However this may be, the really important consideration is that, unless, indeed, there be sometimes a mirage athwart the clouds such as there is occasionally in the desert, the surface of the water, seen from below, can never have any glare at all. From above, a river or a lake is a mirror, reflecting the skies and all that in them is, as well as upstanding objects on the shores; but from below it is no more a mirror than is a sheet of glass without a backing of silver. Thus, such of the phenomena of light as disturb the angler are not in the consciousness of the trout at all. To them, saving amid the exceptional circumstances for which we have made provisional allowance, there is no glare, howsoever fiercely the sun may blaze; no lane of light, even when their glance is eastward at the dawn ; they never see on the surface the blue reflection of the undimmed sky, or the dingy-yellow of the snow-storm, or the inky-purple of the thundercloud.
Are we to conclude, then, that the light is of no importance when one goes fishing ?
That would be as empirical as any of the misapprehensions I have endeavoured to explain away. It is rather more than possible that there may be some truth in a few of the accepted understandings on the subject. What that truth may be I will show immediately. For the moment let us note how easily, on such an illusive subject, misapprehensions, which become convictions, arise.
Only a few of us have the good fortune to fish continuously for months. The rest have to be content with a day, or a few days, at a time. In most cases, then, our craft in angling is derived from experiences far from complete. Nevertheless, it is a settled body of doctrine, of principles unshakably fixed. Our observations by the riverside, or on the lake, are vivid and memorable for their rarity. We had a week, let us say, at Whitsuntide, and sport was good on all the days but one. What are our recollections ? A little introspection will lead to an illuminating discovery. The recollections are in two classes, one of which is vivid in general joy, while the other is vivid in detailed distress. Of the good days we remember how cheerfully the trout rose, where we landed the three-pounder, where the bigger fish broke off, and what merry nights began when we all assembled at dinner; but whence the wind on these days ? Did the sun shine brightly, or was the sky clouded ? Were the days warm, or were they chill ? Was the weather fair, or were there showers of rain ? Our recollections on these points, it will be found, are vague. The sport and the mirthful happiness are very fresh memories indeed; but all we can say about the weather is that, whatever the details may have been, it was certainly exceeding good. Then, the day when the sport was poor: Ah, there is no difficulty on that score! The morning was promising enough ; but we had not been out for an hour before we discovered that the wind was shifty.