Distributing reservoir - . - 0.080 Iron pipes on bridge over Harlem valley - - 0.275 Do. do. across Manhattan valley - - 0.792 Do. do. between reservoirs - 2.176

40.562

It is proper to add to the above, the length of the Croton reservoir, which has been formed by the erection of the Croton dam and other work necessary to obtain the water, at a suitable level on the Croton river, as without this dam and reservoir, the aqueduct would have required an extension of five miles to reach the proper level on the river ;

which is now attained by means of the dam. The entire length, therefore, from the point on the Croton, which has the requisite elevation, to the distrbuting reservoir, is 45.562 miles. The large mains running from the distributing reservoir, through the central part of the city, would add about four miles, making the total length of the main conduit nearly fifty miles.

DESCRIPTION OF THE COUNTRY THROUGH WHICH THE AQ.UEDUCT IS LOCATED. The soil, earth, and rock, of the country from the banks of the Croton to the city of New York, is of one general character. The line cuts a small section of marble of inferior quality, about two miles below the Croton dam. In running through the State farm at Sing Sing, it passes a few hundred feet (mostly by a tunnel) in a marble of pretty fair quality for building and again at Dobbs' Ferry and at Hastings it lightly cuts a similar ;