Without entering into a detailed discussion, it may be said that the amount of sewage, with reference to the size of the river and the volume of flow, is a fraction less than that at Lawrence, Mass., where a filter-plant has also been constructed, but the pollution is much greater than that of most American rivers from which municipal water-supplies are taken. The filtration-plant completed in 1899 takes the water from a point about two miles above the old intake. Pumps lift the water to the sedimentation-basin, from which it flows to the filters and thence through a conduit to the pumping-station previously used. DESCRIPTION OF PLANT. =Intake.=—The intake consists of a simple concrete structure in the form of a box, having an open top covered with rails 6 inches apart, and connected below, through a 36-inch pipe, with a well in the pumping-station. Before going to the pumps the water passes through a screen with bars 2 inches apart, so arranged as to be raked readily. The rails over the intake and this screen are intended to stop matters which might obstruct the passageways of the pumps, but no attempt is made to stop fish, leaves, or other floating matters which may be in the water. The arrangement, in this respect, is like that of the filter at Lawrence, Mass., where the raw water is not subjected to close screening. There is room, however, to place finer screens in the pump-well, should they be found desirable. [Illustration: HUDSON RIVER NEAR INTAKE FIG. 1.] [Illustration: SEDIMENTATION-BASIN, PUMPING-STATION, AND OUTLETS.] [Illustration: SEDIMENTATION-BASIN, AN OUTLET, AND LABORATORY. [_To face page 290._] ] =Pumping-station.=—The centrifugal pumps have a guaranteed capacity of 16,000,000 gallons per 24 hours against a lift of 18 feet, or 12,000,000 gallons per 24 hours against a lift of 24 feet. The ordinary pumping at low water is against the higher lift, and under these conditions either pump can supply the ordinary consumption, the other pump being held in reserve. The pumping-station building, to a point above the highest flood-level, is of massive concrete construction, without openings. Nearly all the machinery is necessarily below this level, and in high water the sluice-gates are closed, and the machinery is thus protected from flooding. The superstructure is of pressed brick, with granite trimmings. =Meter for Raw Water.=—Upon leaving the pumping-station the water passes through a 36-inch Venturi meter having a throat diameter of 17 inches, the throat area being two ninths of the area of the pipe. The meter records the quantity of water pumped, and is also arranged to show on gauges in the pumping-station the rate of pumping.