fluting a falling-head permeability tett the head fell from 50 to 30 cm in 4.5 min. The specimen was 5 cm in diameter and had a length of 90 mot. The we of the standpipe was 0.5 !mi. Compute the coefficient of permeability of the soil in cm/s, m/s, and ft/d. What was the probable elassiticauon of the sod tested? (After A. Casagrande.)