be entirely delusive. This may be explained, without impeaching the sagacity or accuracy of those engineer, by the facts, that they had no actual experi- ence derived from the price at which contracts would be taken — that the difference in the cost of land from that which it bore in 1835, and that afterwards placed on it by speculators and interested persons, was beyond calculation — and that the prices of work and materials were largely enhanced between 1835 and 1837. "The whole project, in fact," say the Com- missioners, " was entirely new, and perhaps without precedent as to cost, and therefore it o%ht not to be considered as a want of talent, that mistakes were made in estimating the expense." In confirmation of these views, and of the great liability to error in estimates for un- dertakings of such a nature and extent, the reader will recall the fact stated in the Prelimi- * nary Essay, that almost all the estimates for the various water works of London, fell vastly short of the actual cost. On the 27th of December, 1837, after he had placed thirteen sections of the first division under contract, and therefore with some practical experience of the value of such work, Mr. Jervis made an estimate of the cost, so far as the engineering was concerned, of the whole line, which amounted to $7,877,346 00 This was exclusive of the cost of land, salaries, and other expenses, which the Commissioners themselves estimated at 586,567 00 $8,464,033 00 For the additional cost of the high bridge, 443,432 00 $8,907,465 00 Nine millions therefore, may be assumed as the cost of the aqueduct, over and above the loss of interest on the capital, until the work be finished and productive. CROTON AQUEDUCT. 177 This report closes with a general recapitulation of the work done, of the difficulties overcome, and of the nature, form, and materials of the aqueduct, all which we propose to present in a connected form, after the narrative of the progress of the work is com- pleted. On the 30th March, 1840, the Commissioners, who, from the commencement of this great enterprise, had directed and superintended its progress, having been superseded, made a final report to the Board of Aldermen. This sets forth the precise condition of the funds which they had received, of which the details, with accompanying vouchers, were communicated to the Comptroller, and the balance in hand paid over to their suc- cessors ; it gives information of the exact condition of the work, and of what had been done since January, and finally adds the satisfactory statement that the whole line of aqueduct had then recently been examined by the chief engineer, who reported very slight injury from a very inclement winter. Having surmounted many and great difficulties in the execution of their trust, having disbursed nearly four and a half million dollars, without the error of a cent in account with the Comptroller, with the whole of the land required for the aqueduct in peaceable possession, with the contracts for the entire works made, and a large portion of them com- pleted— the Commissioners handed over the trust to their successors, whose path was so comparatively plain and easy. Their report thus concludes : The late Commissioners are free to confess, that they feel a deep interest in the success of the work, and would have been pleased, had circumstances permitted, to have continued their superintendence until its completion. They hope, however, that it will be prose- cuted by their successors, in a manner creditable to themselves and beneficial to the public. We leave with them our efficient and highly esteemed chief engineer, John B. Jervis, Esquire, for whose services in the successful prosecution of the work, the public are greatly indebted. The industry and ability with which he has conducted this great enterprise, will carry his name to future time, let who will be charged with its completion. We cannot forbear expressing the hope, therefore, that our successors will avail themselves of the tal- ents and acquired knowledge of Mr. Jervis, for the further prosecution of a work of so much importance to . this city. The advantages in retaining his services, and also of his present assistants, must be obvious ; as the information they possess, relative to the man- ner in which the contracts are to be fulfilled and executed, of the materials to be used, of the plans and specifications in explanation of the several parts of the work to be performed, and of numerous other matters connected with it, will be, in our opinion, of the first impor- tance to those who are to have the supervision of its progress, and an efficient aid in the substantial construction of the work. This