The Settlement of Solid Matter in Fresh and Salt Water

Abstract

SINCE the publication of the report of Mr. Slidell¹ on the deposits of the Mississippi delta, containing the remarkable statement that while the deposit contained in the river water of the Mississippi took from ten to fourteen days to settle, with solutions of salt, sea water or sulphuric acid the water became limpid in from fourteen to eighteen hours, it has generally been taken as an accepted fact that alluvial matter settles more rapidly in salt than in fresh water. Sir Archibald Geikie, in his “Text-book of Geology,” endorses this theory; and in a recent article in the American Engineering Magazine on the transportation of solid matter by rivers, Mr. Starling, one of the Government river engineers, states that a small quantity of salt or other foreign material dissolved in water will diminish the suspending power and increase the rapidity of subsidence to a marked degree, sometimes even many hundred-fold.