WATER WORKS. 



S09 



masonry connecting the pipe with the gate- 

 house, there is a cast-iron cylinder, into which 

 a cast-iron ring, which forms the end of the 

 pipe, is inserted and fitted as a piston. Thus 

 there is a movable joint at each end of the 

 pipe, which, together with the rollers between 

 the planed surfaces of the pedestals and sad- 

 dle*, fully provide for the longitudinal contrac- 

 tion and expansion of the pipe, under any vari- 

 ations of temperature to which it can be 

 subjected. The three rollers on each pedestal 

 are kept in their proper relative position to 

 each other by an iron frame. The surfaces of 

 contact in the pistons and cylinders, at the 

 ends of the pipe, are faced with brass. 



Fig. 3 represents a vertical and transverse 

 section of the bridge, at the centre of one of 

 the arches. It shows the former construction 

 of the top of the bridge and the line of the for- 

 mer gravel covering over the pipes, and also 

 shows the contemplated change in the sides 

 and the proposed covering arch. All the ma- 

 sonry above the line of the old coping, and all 

 the interior brick work, above the points mark- 

 ed A A, will be new work. When 

 finished, the whole interior will 

 be an open chamber, with suffi- 

 cient space around all of the 

 pipes for examination and repair. 

 This chamber will be lighted and 

 ventilated from the roof, and ap- 

 proached by doors, cut into the 

 masonry at the sides of the north 

 end of the bridge, which will be 

 large enough to admit the in- 

 troduction of cast-iron pipe or 

 wrought-iron plate, or any other 

 material for repairs. The roof 

 will be of brick, abutting against 

 cast-iron skew backs, kept in 

 place by wrought-iron tie-rods. 

 The arch will be made water 

 tight by a covering of concrete 

 and asphaltum. 



To keep up the supply of water 

 to the city during the progress 

 of the work iu connecting the 

 new pipe, it was necessary to 

 change the entrance gates of the 

 old pipes, from the front to the 

 side of each gate chamber, and 

 to do this, also, without drawing 

 off the water from the aqueduct 

 and gate chambers. A caisson or coffer dam of 

 wood was framed and sunk to its position, against 

 the inner face of the west wall of each chamber, 

 leaving a narrow space between the masonry 

 and the inner face of the coffer dam. The water 

 from this space was then pumped out. The 

 west walls were then cut away and rebuilt, 

 with the proper variation for new gates, and 

 the reception of the mouth pieces for the 

 two 3-feet pipes. From these points, two new 

 lines of pipes were carried round, on the out- 

 side of the gate houses, and down to the floor 

 of the bridge, to the point at which the re- 



moval of the old pipes was necessary. Hero 

 the pipes were, one at a time, cut off. "am! 

 nected with the new lines leading into th- 

 of the gate house. The water was then passed 

 through the old pipes by these new connec- 

 tions, and the fronts of the gate h< 

 free for further operations. Th< 

 of almost the entire fronts (below the 

 line) was removed in the same manner it had 

 been from the sides, and the new construction 

 went on without interruption. During the 

 whole of this work, there was at no time a 

 stoppage of the entire flow of water into the 

 city. It was not shut off at all, for any of the 

 operations, at the gate-chambers themselves. 



Manhattan Valley Improvements. At this 

 valley there is an interruption of the brick 

 conduit similar to that at High Bridge. As 

 originally constructed, the water was conduct- 

 ed across this valley in 2 3-ft. siphon pipe?, to 

 which was added, in 1853, a 4-ft. pipe. This 

 year a fourth pipe has been added, 5 feet 

 diam., of cast iron, in lengths of 12 ft. 5 in., 

 and l inches in thickness. The average 



FIG. 3 



weight of each length is 11,226 Ibs.. and the 

 aggregate extent of "this line, measured as laid, 

 is 4.116 ft. 



The New Reserr&ir.The water was formal- 

 ly introduced into the new reservoir on the 

 19th of August, with a celebration by the 

 civic authorities, and speeches from the mayor 

 (Mr. Opdyke). and from Myndert Van Schaick, 

 for many years president of the Croton board, 

 and from many others. The reservoir is prob- 

 ably the largest purely artificial construction 

 in the world. Its water surface, when full, 

 is 96 acres, its depth 37 ft., and its capacity 



