here is no essential difference between trout and salmon casting. The same general principles apply to both, and it only requires the careful application of the skill attained in 'the one to become equally expert in the other. The difference is simply the difference in weight. A twelve-foot trout rod weighs, say, eight ounces, and an eighteen-foot salmon rod, with reel, weighs two or three times as much. The one can be manipulated with one hand; the other requires both. With the one you ordinarily cast forty or fifty feet; with the other sixty or eighty; and with rods equally approximating perfection, it is as easy to cast the eighty feet with the one as the forty feet with the other. I do not mean to say that no more muscular exertion is required in the one case than in the other, but simply that with such slight effort as is necessary with either, it is as easy to place your fly where you wish it with the one rod as with the other. No great muscular exertion is necessary to cast with either. Indeed, the chief difficulty in casting is to get rid of the idea that a great deal of muscular effort is necessary to get out a long line. That coveted result is not to be attained by mere muscle. If you have a giant's strength you mustn't use it like a giant. If you do you will never make a long or a graceful cast with either trout or salmon rod. With both there must be only such strength used as is necessary to give the line a quick but not a snappy back movement—keeping up the motion evenly until the fly is placed where you desire it.
The most difficult attainment, in both salmon and trout casting, is to be able, with instinctive accuracy, to measure the distance traversed by the backward movement of your line. If you begin the return too soon your line will snap and thereby endanger your fly; if you are too tardy it will droop and thereby lose the continuity of tension indispensable to a graceful and effective forward movement. This essential art can only be attained by practice. Some attain it readily; others never;—just as some measure time in music with unerring accuracy, without a teacher; some only acquire the art after protracted drilling, and others never acquire it at all.
There is almost as perfect rhythm in fly-casting as in music. Given a definite length of line and the expert can measure his cast by his one, two, three, four, as accurately as a teacher can regulate the time of his orchestra by the movement of his baton. While this is true in casting with either rod it is most noticeable in easting for salmon. The heavy line, the massive springy rod, and the great distance to be traversed, render each movement—the lift from the water, the backward flight of the line, the return motion, and the drop at the point desired—as distinct to a quick perception as the beat of a bar in music.
But there are occasions when it would not do to cast by count. If the wind is strong in any direction the movement of the line is perceptibly effected; and if the wind happens to be at your back, it requires great skill and care to counteract its influence and secure satisfactory results. With such a wind, unless you are perfect master of the situation, you will be apt to snap off more flies in an hour than you will be likely to lose legitimately in a fortnight. Nine-tenths of all the flies I ever lost took their departure before I learned how to cast safely with a high wind at my back.
In many salmon rivers the pools are so placed and the general body of water is of such depth that you can always cast from your anchored canoe. As, under such circumstances, there are no obstructions behind you, less care is required in keeping your fly well up in its backward flight than when casting from the shore—as in some rivers you always have to do.