was three, arid the length 670 feet, together with five partly finished, measuring 610 feet in length, making a total of 1280 feet. Increase in this description of the work 574 feet of tunnelling. Foundation and Protection Wall. The foundation wall laid is 58,439 cubic yards, and of protection wall 36,590 cubic yards; making a total of 95,029 cubic yards. The quantity of foundation wall, laid at our last report, was 28,000 cubic yards, and of protection wall 13,160; making a total of 41,160 cubic yards.. • Increase since our report in July last, 53,869 cubic yards. This is a very limited sketch of the amount of work performed as a whole, and is only intended to convey some idea of the structure and its progress. The immense effort in penetrating high hills, and in crossing deep valleys, can only be judged of by a personal view of the vast amount of labor performed by the physical strength of man." This- Report of the Commissioners, especially in that part of it that commented on the Report made by the Board of Assistants in favor of a high bridge, and on the resolu- tion given in a preceding page, which that Board, in conformity with the Report, passed — seems to have touched that body — and as the Commissioners had alway addressed their communications to the Board of Aldermen, the Assistants passed the following resolution : Resolved, That the Water Commissioners be requested to communicate to this Board, as a constituent branch of the Common Council, a copy of their late semi-annual Report, to the end that this Board may take such action thereon as the nature thereof may require, and that the Clerk forthwith communicate a copy of this Resolution to the said Com- missioners. Adopted by the Board of Assistants, January 2, 1839. CROTON AdUEDUCT. 163 Moreover, the landowners and others, who were contending for the uninterrupted navigation of the Harlem, abandoning their contemplated appeal to the U. S. Courts, ad- dressed themselves to the Legislature. The efforts made were successful, and the follow- ing law was passed on 3d May, 1839. AN ACT PRESCRIBING THE MANNER IN WHICH THE CROTON AQUEDUCT SHALL PASS THE HARLEM RIVER. The People of the State of New York, represented in Senate and Assembly, do enact as follows : § 1. The Water Commissioners shall construct an aqueduct over the Harlem river, with arches and piers ; the arches in the channel of said river shall be at least eighty feet span, and not less than one hundred feet from the usual hiffh water mark of the river to the under side of the arches at the crown ; or they may carry the water across said river by a tunnel under the channel of the river, the top of which tunnel shall not be above the pre- sent bed of the said channel. The Commissioners, who had in vain sought the instruction of the Common Coun- cil on this vexed question, of a high or low bridge, and who had at last, on their own re- sponsibility, decided in favor of the low or syphon bridge, and had actually entered into contract for its construction, were naturally not a little annoyed at the change of plan thus authoritatively forced upon them. Nevertheless, they submitted with a good grace, and, having taken the precaution to insert in the contract a proviso, that if at any time the plan of the low bridge should be abandoned, the Commissioners might vacate the Contract upon paying the contractors for work done, and materials delivered, or bespoken, they at once proceeded, on 6th May, when a certified copy of the act was handed to them, to declare that the contract was abandoned, and to direct their engineers to ascertain the value of the work done, and of the materials delivered under it. They also directed the chief engineer, forthwith to examine and report fully upon the two modes of passing the Harlem, prescribed by the Legislature. This report, made on 1st June, seems of sufficient importance to be given at length. REPORT OF THE CHIEF ENGINEER, ON PLANS FOR CROSSING HARLEM RIVER. New York, June 1st, 1839. To the Honorable the Water Commissioners of the City of New York : GENTLEMEN : — The resolution of your Board, requiring the undersigned to prepare plans and estimates for crossing Harlem River, by a bridge, the arches of which shall be 164 MEMOIR OF THE elevated 100 feet above common high water mark, and also for a tunnel under the channel of the river, has been under consideration. The law passed at the recent session of the Legislature provides, in relation to a tun- nel under Harlem river, that the top of the tunnel shall not be above