supply of water, which now discharges into Long Island Sound, might be diverted or made to pass into the Croton. This fact is mentioned for its singularity, rather than from its being of any importance to the work. The lake, formed by the dam, flows already over some lands not embraced by the deeds or rights obtained by our predecessors ; and when it is considered that it is liable to rise three feet higher than it has yet been, it will be perceived that the extent of our water line must be considerably increased ; but as the surface of the lands subject to be overflown beyond the Corporation title, is mainly of inconsiderable value, the damages will be small. The beautiful sheet of water now formed by the dam, the Board have called the Cro- ton River Lake, as readily distinguishing it from the entirely artificial reservoirs. The highest point of land on the eastern side of it, in a late visit with the Corporation to the Croton River Lake, was named " Mount Varian," in honor of our worthy Chief Magis- trate, during whose mayoralty the works at the Croton River have been commenced and completed. Second Division, commencing at the southern termination of the first division (about three miles south of Sing Sing) and running 10 732-1000 miles to the village of Hastings, is also entirely completed, if we except about 140 yards in length at the Mill River Val- ley, which is a high stone wall and embankment designed to support the aqueduct, and to complete which requires about 20,000 dollars. Third Division, which commences at the southern termination of the second divi- sion, near Hastings, and runs in -a southerly direction 9 669-1000 miles, to within about two miles of the Harlem River. This division is all completed, and the final payments on the contracts are liquidated. Fourth Division, commencing at section 80, terminating the third division, and running to the Battery in the First Ward of the City of New York, distance in all four- teen miles. Of this division, sections 80, 81, 82, 83, 84 to 85, in length about two miles, are in Westchester County, and are entirely completed. The whole distance in Westchester County, all of which is nearly completed, is 32 miles and two-thirds of aqueduct, the arch bridge of 88 feet span at Sing Sing, 12 tun- nels (or under ground excavations for the aqueduct,) whose aggregate length amounts to CROTON AaUEDUCT. 181 4406 feet, 32 ventilators for the escape of the air from the tunnel, and four waste weirs, for the discharge of the surplus water from the aqueduct. The Harlem River Bridge. After leaving the sections of the fourth division in Westchester County, we arrive at section 86, which includes the crossing of the Harlem River, and here we have been engaged with the high bridge. We should be happy to be enabled to state, that this structure could proceed as rapidly as the remaining part of the work, and would be as soon completed. This bridge, it will be recollected, is, by the plan, to be supported by seven land arches, each of 50 feet span, on the valley between the river and the adjacent hills, and over the river by eight arches of 80 feet span each, the crown of the intrados of the arches is 100 feet above the surface of the water, and the height of the superstructure near 120 feet. We have sunk four coffer dams in the river for the river piers, and built the foundations of two piers to above high water mark, and another is about four feet above the foundation. The amount of money spent on the Harlem Bridge, for the work and materials not yet used, amounts to $91,100. Leaving the Harlem River, as you approach the city, we have section 87 of the aque duct, which includes a small tunnel through rock, completed or nearly so ; 88, 89 and 90 are in a great state of forwardness ; when you arrive at section 91, which includes the crossing of Manhattan Valley. This section is a mile in length, and one of the heaviest on the line ; it consists of 800 feet of tunnel cut through rock, and about three-fourths of a mile of grading for two lines of iron pipes of 36 inches diameter. This last section is about one half completed, and will easily be completed the next fall. We then arrive at section 92, which is nearly completed, with the exception of the tunnel, which is 420 feet long, through rock, 120 feet of which is excavated. The next section, No. 93, is com- pleted, and the account settled. Section No. 94 crosses the Clendening Valley, and em- braces a very