Questions of water-filtration. LESLIE. Trans. Inst. Civil Engineers, 1883, lxxiv. p. 110. A short description of filters at Edinburgh. LINDLEY. A report for the commissioners of the Paris Exposition of 1889 upon the purification of river-waters, and published in French or German in a number of journals, among them _Journal für Gas- und Wasserversorgung_, 1890, p. 501. This is a most satisfactory discussion of the conditions which modern experience has shown to be essential to successful filtration. MASON. Engineering News, Dec. 7, 1893. Filters at Stuttgart, Germany, with plans. MEYER and SAMUELSON. Deutsche Bauzeitung, 1881, p. 340. Project for filters for Hamburg, with diagrams. Except in detail, this project is the same as that executed twelve years later. MEYER. Deutsche Bauzeitung, 1892, p. 519. Description of the proposed Hamburg filters, with diagrams. —— The Water-works of Hamburg. A paper presented to the International Health Congress at Rome, March 1894, and published as a monograph. It contains a full description of the filters as built, with drawings and views in greater detail than the preceding paper. MILLS. Special Report Mass. State Board of Health on the Purification of Sewage and Water, 1890, p. 601. An account of the Lawrence experiments, 1888-1890. —— Report Mass. State Board of Health, 1893, p. 543. The Filter of the Water-supply of the City of Lawrence and its Results. —— Trans. Am. Society of Civil Engineers, 1893, xxx. p. 350. Purification of Sewage and Water by Filtration. NEVILLE. Engineering, 1878, xxvi. p. 324. A description of the Dublin filters, with plans. NICHOLS. Report Mass. State Board of Health, 1878, p. 137. The filtration of potable water. OESTER. Gesundheits-Ingenieur, 1893, p. 505. What is the Rate of Filtration? A purely theoretical discussion. ORANGE. Trans. Inst. Civil Engineers, 1890, c. p. 268. Filters at Hong Kong. PFEFFER. Deutsche Bauzeitung, 1880, p. 399. A description of filters at Liegnitz, Germany. PIEFKE. Results of Natural and Artificial Filtration. Berlin, 1881. Pamphlet. —— Journal für Gas- und Wasserversorgung, 1887, p. 595. Die Principien der Reinwassergewinnung vermittelst Filtration. A sketch of the theory and practical application of filtration. —— Zeitschrift für Hygiene, 1889, p. 128. Aphorismen über Wasserversorgung. A discussion of the theory of filtration, with a number of experiments on the thickness of sand-layers, etc. PIEFKE. Vierteljahresschrift für Gesundheitspflege, 1891, p. 59. On filters for city water-works. FRÄNKEL and PIEFKE. Zeitschrift für Hygiene, 1891, p. 38. Leistungen der Sandfiltern. An account of the partial obstruction of the Stralau filters by ice, and a typhoid epidemic which followed. Experiments were then made upon the passage of cholera and typhoid germs through small filters. PIEFKE. Journal für Gas- und Wasserversorgung, 1891, p. 208. Neue Ermittelungen über Sandfiltration.