Water-Supply Engineering: The Designing, Construction and Maintenance of Water-Supply Systems, both City and Irrigation. . By A. Prescott Folwell, Associate Professor of Municipal Engineering in Lafayette College. First Edition. New York, John Wiley and Sons. 1900. Octavo, 562 pages and 19 plates. Price, $4.00.; The Filtration of Public Water-Supplies . By Allen Hazen. Third Edition, Revised and Enlarged. New York, John Wiley and Sons. 1900. Octavo, 321 pages and 22 plates. Price…