Quicksand
in its usual significance, a tract of sand which, without differing much in appearance from the shore of which it forms part, remains permanently saturated with water to such an extent that it cannot support any weight.
Quicksands are most often found near the mouths of large rivers. They appear only to be formed on flat shores, the substratum of which is an irregular expanse of stiff clay or other impervious formation. Pools of water are retained in the hollows, and become partially filled with sand or mud, which remains like the soft sediment in a cup of cocoa on account of the absence of drainage. The sand on a uniform shelving shore consolidates at low tide because the water which permeates it drains back freely to the sea. In narrow channels through which the configuration of the adjoining shore causes strong tidal currents to run the sand may be kept so constantly stirred up by the moving water that a quicksand results. Thus, while the summit of a sandbank rising from a gentle slope is usually firm, the hollow margin of the bank where it meets the shore is usually frequently a quicksand.
Quicksand, when examined under the microscope, will be seen to have rounded corners like river sand, as distinguished from angular or "sharp" sand, which will pack more solidly than the other.
It is quicksand that is used in the hourglass and in the smaller egg-boiler. Quicksands are not commonly of great extent, and their danger has probably been exaggerated in the popular mind by sensational descriptions in works of fiction. The name quicksand is sometimes applied to the drifting sands which are carried by wind over cultivated land bordering the seashore or a desert.
QUICKSILVER. See MERCURY.