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 discovered, by appearances on the outside, or examinations by means of a boat floating through the inside. The latter should be done generally once in each month, and more frequently on parts most liable to prove defective. In addition to this, it should be established as a rule, that the water is to be shut off twice in a year, for a thorough inside examination, when all repairs that may appear necessary should be made. With suitable preparations, the examination and work required could ordinarily be accomplished in about ten days, during this time, the reservoirs would amply supply the city with water. With proper regulations, they would give a sufficient supply to 500,000 people for double the time proposed. The most suitable time for such examinations would be early in the months of April and November, when the temperature of the water in the reservoirs would not be materially affected. The water has usually flowed at the depth of two and a quarter feet in the aqueduct, but has been as- high as three and a half feet, and between the Croton Dam and Sing Sing waste wier (nearly 8 miles) was for several weeks from five to six feet deep. The water in the receiving reservoir has been gradually raised to its present height of eighteen feet in the northern division, and twenty-six feet in the southern division.