Page:Africa by Élisée Reclus, Volume 1.djvu/98

 of the marine currents than on the inland floods. But if its height is little modified, its position is often shifted several miles. During the inundations the current of the Nile is felt 3 miles seawards, and at times is strong enough to perceptibly reduce the violence of the waves, thus offering a temporary refuge to storm-tossed vessels.

The face of the delta is gradually encroaching on the sea, but at a much slower rate than might be expected from the quantity of sedimentary matter brought

down by the Nile. Even the estimate of 13 or 14 feet annually, as calculated by Elie de Beaumont on a study of the old and mediæval documents bearing on this point, seems to be excessive, slight though it be when compared with the growth of even smaller deltas, such as those of the Rhine and Po. The charts prepared by the French expedition at the end of the last century, and by M. Larousse in 1860, after the completion of the preliminary works for the Suez Canal, give a yearly increase of 130 feet for the Rosetta and 40 for the Damietta mouth. But these are merely local changes, and with the displacement of the channels the