reaches the left bank of the Hudson, which it pursues, keeping at a distance of nearly half a mile from the River, until it arrives at the village of Sing-Sing, which is eight miles from the dam. In the course of this distance the Aqueduct passes through four tunnels and encounters many valleys and ravines where high foundation walls were required, and culverts for the passage of the streams. At the village of Sing-Sing there are two Aqueduct bridges ; one over a public road-way, and the other over the Sing-Sing Kill. These bridges and the adjacent work form a very interesting point on the line of Aqueduct. Plate XII. is a view of the Aqueduct at this place : at the

left of the picture may be seen the bridge over the road, and on the right that over the Kill. The bridge over the road has a span of 20 feet, and the direction of the road-way be-

;

ing not at right angles with the line of Aqueduct required the arch to be built askew ; the arch lies in the direction of the road-way, having the ends in planes parallel with the direction of the Aqueduct. This bridge is worthy of notice, but public attention is more generally directed to the larger one : that has an arch of 88 feet span and a rise of 33 feet the form of the arch is elliptical, being a compound curve drawn from five different centres, or radius points. The Kill, or valley over which this arch stands, is a deep narrow