Salient points in judging of the work of sand-filters. HALBERTSMA. Journal für Gas- und Wasserversorgung, 1892, p. 43. Filter-works in Holland. Gives sand, gravel, and water thickness, with diagrams. —— Journal für Gas- und Wasserversorgung, 1892, p. 686. Description of filters built by the author at Leeuwarden, Holland, with plans. HART. Proceedings Inst. of Civil Engineers, 1890, c. p. 217. Description of filters at Shanghai. HAUSEN. Journal für Gas- und Wasserversorgung, 1892, p. 332. An account of experiments made for one year with three 16-inch filters at Helsingfors, Finland, with weekly analyses of effluents. HAZEN. Report of Mass. State Board of Health, 1891, p. 601. Experiments upon the filtration of water. —— Report of Mass. State Board of Health, 1892, p. 539. Physical properties of sands and gravels with reference to their use in filtration. (Appendix III.) HUNTER. Engineering, 1892, vol. 53, p. 621. Description of author’s sand-washing apparatus. KIRKWOOD. Filtration of River-waters. New York, 1869. A report upon European filters for the St. Louis Water Board in 1866. Contains a full account of thirteen filtration-works visited by the author, and of a number of filter-galleries, with a project for filters for St. Louis. This project was never executed, but the report is a wonderful work which appeared a generation before the American public was able to appreciate it. It was translated into German, and the German edition was widely circulated and known. KOCH. Zeitschrift für Hygiene, 1893. Water-filtration and Cholera: a discussion of the Hamburg epidemic of 1892 in reference to the effect of filtration. KRÖHNKE. Journal für Gas- und Wasserversorgung, 1893, p. 513. An account of experiments made at Hamburg, as a result of which the author recommends the addition of cuprous chloride to the water before filtration to secure greater bacterial efficiency. KÜMMEL. Journal für Gas- und Wasserversorgung, 1877, p. 452. Operation of the Altona filters, with analyses. —— Vierteljahresschrift für Gesundheitspflege, 1881, p. 92. The water-works of the city of Altona. —— Journal für Gas- und Wasserversorgung, 1887, p. 522. An article opposing the use of rapid filters (David’s process). —— Journal für Gas- und Wasserversorgung, 1890, p. 531. A criticism of Fränkel and Piefke’s results, with some statistics of German and English filters. (The English results are taken without credit from Kirkwood.) —— Vierteljahresschrift für Gesundheitspflege, 1891, p. 87. Discussion of papers on filtration, with some statistics. —— Vierteljahresschrift für Gesundheitspflege, 1892, p. 385. The epidemic of typhoid-fever in Altona in 1891. —— Journal für Gas- und Wasserversorgung, 1893, p. 161. Results of experiments upon filtration made at Altona, and bacterial results of the Altona filters in connection with typhoid death-rates. —— Trans. Am. Society of Civil Engineers, 1893, xxx. p. 330.