Excerpt from The Construction of Sand-Clay and Burnt-Clay Roads The two properties of clays which are of the greatest importance from the standpoint of road building are, first, plasticity, and second, the property of slaking when they first become wet after having been uncovered. A clay is called plastic which becomes sticky or dough like when mixed with a certain amount of water, so that it can be molded or pressed into various shapes which it will retain even after it has been dried. The most plastic of these materials are known technically as ball clays. If a lump of such a clay as this is immersed in water it will usually preserve its form for a long time. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.