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

gorge worn by a small stream which empties into the Hudson River. The bottom of the ravine is about 70 feet below the soffit or under side of the arch. Plate XIII. is another view of the large arch taken from the bottom of the valley near it, and shows the bridge which has been constructed for a public road passing under it, and the mill near by.

This arch presents a singularly bold appearance, vaulting over the roadway and rising high up above the old mill, and

what adds much to this boldness, is the narrowness of the arch, or small distance from one end of it to the other ; being only 23 \ feet long at the springing line while the span is

nearly four times this length. The length of the arch diminishes towards the crown, the ends being in planes not vertical, but inclining towards each other at the top. Each end has a batter or inclination of one twenty fourth of its height, or half an inch to the foot. The arch is built of granite, is 3 feet thick at the crown and 4 feet at the spring or base.