Excerpt from Investigation of Commercial Masonry CementsWater-repellent materials were present in about half of the cements as shown in table 1. These materials were apparently added to the cements for increasing either or both the water-repellent or plastic properties of mortars made from them The amount of material identified as a petroleum product varied from to percent, that as fatty acid with three exceptions was less than percent. The 3 exceptions contained and percent. Numbers 34 and 39 contained water-repellent materials, but in such small quantities that they could not be identified.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.