difficulties of such a work and the uncertainty of arriving at a proper estimate of the cost.

In the alternative to which they were driven by the Act of the Legislature, the plan of an Aqueduct bridge of masonry was adopted as the proper one for crossing the

River ; but in establishing its altitude they complied only with the requisitions of the law, and made the soffit or under side of the arches at the crown, 100 feet above common high

water level. This would not carry the work up to the level of the Aqueduct, and would render it necessary to connect the Aqueduct on each side of the valley by iron pipes which would descend to the level of the bridge and crossing it rise again to the masonry channel-way. The plans which were before spoken of for a bridge of masonry across this valley, contemplated a structure which would maintain the regular inclination of the Aqueduct ; and the channel-way would have been formed of masonry having a cast iron lining ; but a more full consideration of the subject suggested the propriety of using iron pipes over the bridge, even if it had been carried up to the grade plane of the Aqueduct when the use of iron pipes was determined upon, then :

considerations of economy induced them to build the work only high enough to comply with the requirements of the law. The plan which has been adopted for building an Aqueduct bridge across this valley is as follows : on the south shore of the river there is one arch of 50 feet span, across the river there are eight arches, each of 80 feet span, and on the north shore there are six arches each of 50 feet span making a range of fifteen arches.