From the north abutment of the arch, to the Westchester side of the river, will be constructed an embankment of stone, by casting them into the river until a sufficient bed shall be formed to support the foundation wall of the aqueduct. From the south abutment pier of the main arch, on the New York side of the river, an arcade, of three arches, will be built, one of 35, one of 30, and one of 25 feet span and, connected with this, a foun- ;

dation wall will be carried up to the ascent, until it reaches the grade level, where the foundation and side walls are to be laid, to receive the pipes entering the effluent pipe

CROTON AdUEDUCT. chamber. The foundation walls, extending from the arcade of arches, and from the abutment of the channel arch, are to be formed of dry masonry, except two feet, constituting the face, and two feet across the top, to form the bed for the iron pipes, all of which to be laid in cement mortar. A parapet wall will be laid on each side of the bed of the pipes, to support the earth covering, which is to be four feet deep above the pipes, to protect the water from the effects of frost.

There will be an influent pipe chamber at the termination of the aqueduct on the north, or Westchester side of the river, in which the pipes are to be inserted. Commencing on this side of the river, at the influent pipe chamber, the pipes descend nearly with the slope of the hill, forming an angle near its base, and thence to the lowest level which ;