A description (in Dutch) of the Rotterdam water-works, including the wooden drains which caused the trouble with crenothrix, and which have since been removed. Diagrams. VAN IJSSELSTEYN. Tijdschrift van het Koninklijk Instituut van Ingenieurs, 1892-5, p. 173. A description of the new Rotterdam filters, with full drawings. VEITMEYER. Verhandlungen d. polyt. Gesell. zu Berlin, April, 1880. Filtration and purification of water. WOLFFHÜGEL. Arbeiten aus dem Kaiserliche Gesundheitsamt, 1886, p. 1. Examinations of Berlin water for 1884-5, with remarks showing superior bacterial efficiency with open filters. —— Journal für Gas- u. Wasserversorgung, 1890, p. 516. On the bacterial efficiency of the Berlin filters, with diagrams. ZOBEL. Zeitschrift des Vereins deutsche Ingenieure, 1884, p. 537. Description of filters at Stuttgart. OTHER LITERATURE. Many scientific and engineering journals publish from time to time short articles or notices on filtration which are not included in the above list. Among such journals none gives more attention to filtration than the _Journal für Gasbeleuchtung und Wasserversorgung_, which publishes regularly reports upon the operation of many German filters, and gives short notices of new construction. The first articles upon filtration in this journal were a series of descriptions of German water-works in 1870-73, including descriptions of filters at Altona, Brunswick, Lübeck, etc. Stenographic reports of many scientific meetings have been published, particularly since 1890, and since 1892 there has been much discussion in regard to the “Rules for Filtration” given in Appendix I. A Report of a Royal Commission to inquire into the water-supply of the metropolis, with minutes of evidence, appendices, and maps (London, 1893-4), contains much valuable material in regard to filtration. The monthly reports of the water examiner, and other papers published by the Local Government Board, London, are often of interest. The German “Verein von Gas- u. Wasserfachmänner” prints without publishing a most useful annual summary of German water-works statistics for distribution to members. Many of the statistics given in this volume are from this source. Description of the filters at Worms was given in the _Deutsche Bauzeitung_, 1892, p. 508; of the filters at Liverpool in _Engineering_, 1889, p. 152, and 1892, p. 739. The latter journal also has given a number of descriptions of filters built in various parts of the world by English engineers, but, excepting the articles mentioned in the above list, the descriptions are not given in detail. MORE RECENT ARTICLES. The following are a few of the more important articles which have appeared since the first edition of this book. In addition many articles of current interest have appeared in the technical journals, particularly in the journals mentioned above. CLARK. Reports of Mass. State Board of Health, 1894 to 1897, inclusive.