Liquid Limit Determination of Arable Topsoils Using a Drop‐cone Penetrometer

Summary The drop‐cone method, in which a 30° cone of mass 80 g is allowed to sink into a soil sample at a selection of moisture contents, is described and examined as a possible alternative to the Casagrande device for liquid limit determination. The methods are compared for 13 arable topsoils. The drop‐cone method, which uses apparatus that is readily available commercially, is shown to have advantages in ease of conduct of the test and in greatly improved reproducibility between operators.