Page:Popular Science Monthly Volume 28.djvu/568

552 the current, and likewise exposed the fallacy of the declaration that there is no relation between the quantity of sediment carried in the water and the velocity of its current.

Mr. Eads thus clearly outlined, in 1874, 1876, and 1878, one of the most magnificent plans which hydraulic engineering has ever undertaken. It is not simply to save thirty thousand square miles of land as rich as the Delta of Egypt from devastating inundations, but to extend deep water from the Gulf of Mexico to the mouth of the Ohio, into the very heart of the Mississippi Valley, while permanently locating this magnificent channel by practically putting an end to the caving of its banks. During the period we have referred to, Mr. Eads delivered addresses upon this subject in the chief cities of the river, published elaborate essays in which it was fully explained, and defended it against all attacks, until finally, in 1879, Congress authorized the creation of a commission to consider this plan, which is known as the "jetty system." The "outlet system" and the "levee system" were also examined by it, and in 1880 it reported in favor of the "jetty system," and recommended its adoption by Congress in its report, February 17, 1880. Mr. Eads was a member of the commission for two or three years. During this period, several million dollars were voted by Congress to carry out the plan, which will be found described in the report referred to, as agreeing substantially with the quotations we have made. Two reaches of the river, Plum Point, twenty miles long, and Lake Providence, thirty-five miles long, were selected for improvement; the low-water depth in the first reach was only five feet, the other reach (four hundred miles below) had a depth of only six feet. The permeable contraction-works, constructed of piles and willows, which had been first used by Mr. Eads at the South Pass several years before, were put in position for one season in the period between two floods, and the effect produced by the works during the first flood that followed was simply marvelous. The depth was increased through the upper reach to twelve feet at low water, and through the lower reach to fifteen feet, and scores of millions of cubic yards of sediment were deposited between them by the checking of the current by the permeable works. Thus new shore-lines of an approximately uniform width were developed. In some places the deposit was thirty feet deep.

Mr. Eads was, during the time of this construction, in bad health, and for some time absent from the United States. Owing to the charge made by several prominent friends of the river (members of the Senate and House), that the commission had abandoned the leading feature of the system, the contraction-works, and had changed it to a costly system of bank-revetments, and the public declarations of Mr. Eads to the same effect, no further appropriations were made at the last session of Congress to continue this magnificent work; enough has been done, however, to show the entire practicability of the plan.