Excerpt from On the Erosive and Abrading Power of Water: Upon the Sides and the Bottom of Rivers and Canals Mr. Thomas Login, Mem. Inst. C. E., in the Artisan, 1869 - 32, also speaks of the whirling or rotary motion of water as effecting scour. Says he, in Speaking of the way in which bridges and other works that guide water should be built, in order that they may not cause the water to undermine their foundations, the engineer must take care that the water flows Off smoothly, that is, that there be as few eddies as possible on leaving the works; but as this rolling or whirling motion cannot on all occasions be avoided, a slight increase of sectional area is necessary. Again, in nature, we never find that water flows in straight lines, but has either a whirling, or what appears to be a rotary motion, that is, any particle of water moving down a stream would follow the course of any point on the perimeter of a carriage wheel rather than that of the axes. On the other hand, in speaking of the Solani aqueduct, a perfectly smooth, uni form channel, with perpendicular sides, and having no Obstructions, either from bends or from irregularities of the bed, with a volume of water, nearly equaling 3000 cubic feet per second 85 feet wide, and over 900 feet long, 82 feet deep, and a bottom velocity of 260 to 380, averaging feet per second, Mr. Login found that a deposit Of sand had actually taken place where the bottom velocity was three times what would be sufficient for transporting sand. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.