Experimental abrasion; 3, Fluviatile action on sand

Abstract

Former experiments by the author dealt with pebble sizes down to 1 cm. The present investigation extends to sizes of 0.4 mm. The mechanism was again that of a current in a circular channel of concrete, but additional tests were made in revolving cylinders. Limestone, feldspar, and mainly quartz, were used. In these sizes mechanical abrasion is found to be entirely negligible in river transport. The elimination of limestone and feldspar during fluviatile transport is therefore not a result of mechanical action. Down-current variation in roundness must be attributed to shape-sorting and/or chemical attack, or to addition from new sources.