Excerpt from Minutes of Proceedings of the Institution of Civil Engineers, Vol. 58: With Other Selected and Abstracted Papers; Session 1878-79; Part IVIn constructing such pavements it is desirable that the upper layer of large stones should be of smaller size than is necessary for concrete, and that they should not be harder than limestone. The still smaller stones and riddlings should be' similarly limited in hardness. The object of this proviso is that the asphalt between the stones may not wear down much more rapidly than the stones, and thus leave in time an uneven surface. The proper consi steney of the asphalt is of even more importance than when it is simply used for joints. About square yards have been laid in Liverpool, and on sanitary grounds the system will probably be extended annually over large numbers of back streets.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.