expected." The whole amount expended on the works up to 20 January, is stated by the Com- missioners at seven millions nine hundred and ten thousand four hundred and seventy- six dollars, to which a further amount of $662,540, required for work unfinished and contracts unsettled, would be added. Both these sums, however, are exclusive of the pipes laid from the distributing reservoir, that head of expenditure being under the charge of the Corporation. The certainty of an adequate supply of water from the reservoirs, even when the aqueduct is under repair, is thus strongly stated in this Report. " The capacity of the reservoirs (perhaps beyond the wants of the city) is making good the opinions of the present Board when they first entered on their duties ; this was manifested on the late occasion of examining the interior of the aqueduct ; the water was shut off and not permitted to enter the reservoirs for ten days ; in these ten days, all the water used in the city for fires and culinary purposes and waste (though the jets d'eau were not playing) reduced the quantity of water in the reservoirs only one-tenth. The water held back in the receiving reservoir would, at this rate, have been sufficient to supply the city for 100 days. The capacity, too, of the receiving reservoir was con- siderably diminished by not excavating to the depth contemplated by the original plans. The aqueduct had now been several months in operation, through summer heats and winter cold — and of course it became a subject of deep interest to ascertain how the work had stood. We copy from the report of Mr. Jervis to the Commissioners on 16th January, this interesting detail on the subject : No interruption to the supply of water to the city has occurred, since its first intro- duction. The water continued to flow uninterruptedly through the aqueduct, from the 22d of June, when it was first let in, to the 8th of November, when it was shut off for the purpose of more effectually inspecting its condition, and the effect that had been pro- duced by the action of the water or other cause. Previous to the time of shutting off the water, several examinations, similar to that mentioned in my report of July last, had been made by myself and the resident engi- neers, Messrs. French & Hastie, by means of a boat floating through the aqueduct, between the Croton Dam and Harlem River. Some unimportant defects were discovered inside the aqueduct, a short time before the water was shut off, and two small leaks ap- CROTON AdUEDUCT. 199 peared on the outside. The next day after the water was shut off, I commenced an ex- amination inside the aqueduct, in company with one of your Board, Mr. Ward, and the resident engineers, Messrs. French & Hastie, on their respective districts, and continued it through the entire aqueduct. For that part on this island, our party was increased by the addition of Messrs. Ring & Birdsall, and Mr. Allen, the principal assistant engineer. On the examination we were accompanied by men prepared to attend to any work that might appear necessary ; and as soon as we passed over a district, they received their directions, and immediately proceeded with such work as it was considered expedient to do. Some defects were discovered, the greater part of which appeared to have been over- looked in previous examinations, which now were discovered, most probably from the clean state of the masonry, after a washing of near five months ; there was, however, evidence that a small additional settlement had taken place in a few instances. The work required was vigorously prosecuted to completion, and on the 16th, eight days after the water was shut off, it was again let into the aqueduct. In the main, the aqueduct appeared substantially well, and the defects not such as to give serious apprehension that its successful action would have been impaired by them for a long time. Enough, how- ever, was discovered to show the propriety of the examination. The two leaks that had appeared on the outside were successfully stopped by the work done inside, and nothing has since appeared to indicate any defect in the work. The reservoirs, during the time the water was shut off from the aqueduct, proved amply sufficient for the supply of the city, and indeed much beyond a supply, as a large quantity of water had to be wasted from the receiving reservoir before the lower end of the aqueduct could be examined. By a proper watchfulness, any material defect in the aqueduct may be timely dis- covered, by appearances on the outside, or examinations by means of a boat floating through the inside. The