system could be operated with less difficulty and with somewhat less expense.
In 1896 the city of Pittsburg, Pa., appointed a commission to consider the character of the water supply and the advisability of its purification by some means of filtration. The supply is taken from the Allegheny and Monongahela rivers, streams which are often turbid and which are subject to contamination by sewage. The conditions were such that direct experiment was necessary to determine the most suitable system of purification. Accordingly, an experimental station was located on the shore of the Allegheny River and placed in charge of Mr. Morris Knowles, under the direction of Mr. Allen Hazen, Consulting Engineer. Arrangements were made for the comparative study of sand filters and mechanical filters, and a laboratory was built and equipped for making all necessary analyses. The plant was in continuous operation for more than a year, and the results seemed to show that while satisfactory clarification of the water could be obtained by either system, the method of sand filtration could be depended upon to remove more completely the effect of pollution.
The report of a similar series of experiments made to determine the feasibility of purifying the water of the Potomac River at Washington, D. C, has been issued by the War Department. The work was carried on in a manner similar to that at Cincinnati and Pittsburg, the object of the studies being to find the best method adapted to the local conditions. Col. A. M. Miller, XJ. S. A., had charge of the investigations, and Mr. Robert Spurr Weston conducted the analytical work. Recently the Department of Public Works, of Philadelphia, Pa., has established a testing station near the Spring Garden Pumping Station for the purpose of studying the problems of filtration incident to the construction of filter beds for the water supply of the entire city, for which the sum of ten million dollars has been already appropriated. The work is in charge of Mr. Morris Knowles. Still more recently a testing station has been established by the Sewerage and Water Board of New Orleans, with Mr. Robert Spurr Weston as Resident Expert.
In July,1899,the newly-constructed water filtration plant at Albany, N. Y., was put in operation, Mr. Allen Hazen having been Chief Engineer of construction and Mr. Geo. I. Bailey Superintendent of Water Works. In connection with this plant is a small laboratory in which are made daily bacteriological examinations of the water before and after filtration. Physical, chemical and microscopical examinations are also made at frequent intervals. The results obtained indicate the amount of purification that is taking place, and they already have shown that the filter is rendering efficient service in protecting the community from water-borne diseases.
The combined work of these various laboratories of supervision and
