Note 1: ,The equipment and procedures are similar as those proposed by R. R. Proctor (Engineering News Record—,September 7, 1933) with this one major exception: his rammer blows were applied as “,12 inch firm strokes”, instead of free fall, producing variable compactive effort depending on the operator, but probably in the range 15 ,000 to 25 ,000 ft-lbf/ft³ ,(700 to 1200 kN-m/m³). The standard effort test (see 3.1.4) is sometimes referred to as the Proctor Test.