VI. Experimental demonstration in respect to the origin windings of rivers in Alluvial Plains, and to the mode flow of water round bends of pipes

Abstract

In a paper which I had the honour of submitting to the Royal Society rather more than a year ago, and which is printed in the ‘ Proceeding for May 4, 1876,I proposed, on hydrokinetic principles, a theoretic view of the mode of flow of water round bends of rivers and of pipe and offered under that view explanations of the origin of the winding of rivers flowing through alluvial plains. Wishing to bring under tl test of experiment the views then put forward, and to render very clear perceptible the phenomena anticipated, I constructed, in the summer 1876, a small artificial river, about eight inches wide and an inch or t> deep, having a bend turning about a half-round, or 180°, so that tl course of the river might be likened to the capital letter JJ. The wat flowing in this river showed very completely, and very remarkably, tl phenomena which had been anticipated, and which are to be four described in the paper referred to. The courses of the water’s flow the various parts of the river, along the bed, and at the upper surfao f$9| and at places anywhere within the body of the current, were made f * show themselves in several ways. One way was by means of threads i j suitable length (about an inch or two long), some of which were anchorc at bottom, while others were attached at various depths in the river ' pins or slender wires standing upright like thin posts in the river. Thef threads, by the lines of direction which they assumed, showed very we ■ the directions of the flow at bottom and at various depths. Anoth* way, and one which proved very satisfactory for showing the bottom cui rents, was by dropping into the river granules of various kinds, such s nd. and peas selected of good round form, and other small round seeds, ch as clover-seed and poppy-seed. Granules such as these showed ,ry clearly numerous phenomena, not only of the flow of the water, but so of the transmission of material-like detritus forward along the jttom in straight parts, and very obliquely across the bottom in the snd; and gave imitations on a small scale, easy for observation, of the rocesses of accumulation of detritus along the inner banks of the bends | rivers, and presented also interesting suggestions and considerations j to some of the details or secondary actions involved in the processes.