The disposal plant was constructed under the supervision of the Iowa Engineering Company of Clinton, Iowa, on a 15 acre tract of land, one and a half miles south of the city. Although original plans called for 18 beds with five feet of gravel, only four beds each 275 feet by 75 feet were finished, and instead of 5 feet of ground only 24 inches was used. The plant was complete in July 1899 and was operated until December, when it was discontinued on account of cold weather, it not being considered necessary to operate it during the winter. From December until April the sewage was discharged directly into a creek which runs along one side of the land. The beds have no automatic device for distributing the sewage at definite intervals of time, but are connected with the main sewer by a number of gate valves which were regulated by the attendant. The sewage is distributed by means of a wooden sluice way which extended the entire length of the bed and has six inch openings on the side every 16 feet which gave a fairly even distribution. Although no analysis of the sand and gravel was made, it was apparent that the uniformity coefficient was very large. The material was shipped a distance of 90 miles and resembles ordinary ballast used for rail roads. The largest pieces were thrown along the sluice way to prevent excessive washing. The finest of the sand was of a size which would be considered too fine for good mortar sand. No attempt was made to screen the material. The gravel would not be considered first class for filtering beds. Samples of the sewage and effluent were taken at two different times. The first was between 9:00 and 10:30 A. M., April 20, 1900. Until the day before no sewage had been applied to the beds since last fall. The second collection was made two weeks later, when samples of the sewage and effluent were collected at intervals of one hour during the day, and mixed into composite samples. The sewage was taken from a manhole just above the beds, and the effluent from the outlet of the underdrain about 900 feet below the beds. The analysis is given in Table I. and the results show that the beds are not working as efficiently as might be expected from a first class plant. This may be accounted for from the fact that the filtration is too rapid and that the material which is less than two feet in depth is not suitable for such a purpose. TABLE I. Analyses of Sewage and of Effluent from Intermittent Downward Filtration Plant at Mendota, Ills.