draws from the southern division at G, and a branch of it passing along within the vault draws from the northern division at H. Provision has been made on the east side of the Reser- voir for supplying that part of the city when it becomes necessary. At present there are two pipes leading from this to the Distributing Reservoir, each 3 feet interior diameter, and they are arranged that both may draw from the southern division, or one from that, and one from the northern divi- sion. The pipes are placed at a level below the bottom of the division from which they draw : the bottom of the inte- rior of those from the southern division being 2 feet below, and that of those from the northern 5 feet below. The exterior walls of this Reservoir present a face of rough-hammered masonry, finished in a manner to give them neatness and durability. As a specimen of mechanical work, this Reservoir will not bear a comparison with the lower, or Distributing Re- servoir, yet the sheet of water it presents, renders it an object of perhaps greater interest. This beautiful lake of pure water resting upon the summit of the Island is truly a plea- sing object, and considering its size, is what no other city can boast of having within its limits. The Distributing Reservoir is situated on the west side of the 5th Avenue between 40th and 42nd streets ; it is two miles from the Receiving Reservoir, and about three miles from the City-Hall. The question may naturally be asked, why this Reservoir t , 119 was built, when the receiving one, of such great capacity, is so near at hand ? The reason for building it, was to obtain an efficient head of water near to the densely populated parts of the city, and had the formation of the island been favorable, the Receiving Reservoir would undoubtedly have been located farther down, bringing the store of water more nearly in the centre of the city. Plate XXIV. is an isometrical view of the Distributing Reservoir showing the front on the 5th Avenue and on 42nd street. The pipes which leave the Receiving Reservoir follow along the 5th Avenue until they reach 42nd street, where they turn and enter the Distributing Reservoir at the base of the central pilaster in that street, which in the drawing is shown on the right hand side. The pipes enter at the bottom of the Reservoir and the flow of water is regulated by stop- cocks : the door in the pilaster affords an entrance to the vault where these stop-cocks are situated. The Reservoir is divided into two separate divisions by a wall. It is de- signed to have three pipes, each 3 feet diameter, to lead from the Receiving to the Distributing Reservoir and arrange- ments are made to discharge water from two of them into one division of the Distributing Reservoir at a time, or the water may be divided into an equal supply for both divisions. On the south side of the Reservoir a pipe of 3 feet diame- ter leaves each division and they are arranged with branch- es so as to draw from one or both divisions. The house standing across the division wall is directly over the mouth of the effluent pipes, and is constructed like those at the Receiving Reservoir, with a gate and screen frame of timber. 120 The central pilaster on 40th street has an entrance (like that on 42nd street) to the vault where the stop-cocks are situated which regulate the discharge from the Reservoir. The pipes leave the Reservoir at the base of this pilaster and from 40th street, curve into the 5th Avenue, which they pursue until they reach a convenient point for diverging to the densely populated parts of the city. This Reservoir is 420 feet square on the top, measuring on the cornice of the main wall ; it is 425 feet square at the top of the cornice of the pilasters, and 436 feet square at the base, measuring from outside to outside of the corner pilas- ters, covering a little over four acres. The height of the walls is 45 feet above the streets around, and about 50 feet above the foundations. The water is 36 feet deep when it reaches the level de- signed for its surface (which is 4 feet below the top of the walls) and the surplus, when the Reservoir is full, passes into a well in the division wall and is conducted by a sewer in 42nd street to the Hudson River, which is one mile distant. The Reservoir is calculated to hold 20,000,000 gallons. The outside walls are constructed with openings in them so that by entering