628 TRANSACTIONS OF THE 



has sliding gates and wire screws at its mouth, which are placed 

 in proper vertical grooves in the masonry, and these are protected 

 by a small brick gate-house erected over them, which in its 

 turn is protected by a row of piles driven a few feet in front 

 of it, and parallel with the course of the river. The pump- 

 well, into which the water is received from the conduit, is 

 divided into two parts by a wall through its centre, making 

 each, twenty-six feet nine inches, by sixteen feet three inches. 

 Large arched openings are formed in the lower part of this wall, 

 for the passage of the water, and it is carried up through the 

 engine-house to the same height as the beam walls, dividing it 

 into two equal and similar engine rooms. The pump-well was 

 sunk to the red sandstone rock which underlies that region, and 

 which, though somewhat loosely stratified, was found sufficiently 

 firm to sustain the weight of the pump, together with the water 

 which it contains, and the plunger loaded to the extent required 

 to raise the water into the receiving reservoir. The foundation 

 for it was prepared by simply levelling and smoothing that part 

 of the rock on which the pamp stands. 



The engine house, which is a handsome brick structure, 127 

 feet in length, including the boiler house, and 39 feet in breadth, 

 was built and fitted for receiving two Cornish pumping engines, 

 with steam cylinders of 80 inches diameter, and stroke of 1 1 feet, 

 each intended to work a pump with a stroke of 11 feet, and 

 plunger 34J inches in diameter. But one of these is yet erected; 

 the present demand for water not requiring half the power of the 

 one now in operation. But as the consumption is constantly in- 

 creasing, the time may not be far distant when it will become 

 necessary to provide the means for increasing the supply. 



The Rising Main, which at present passes out through the side 

 of the engine house, in the rear, is 36 inches in diameter, and 

 2305 feet in length. It is taken through the embankment of the 

 receiving reservoir at its nortliwest angle, on a level with the 

 bottom, from which it rises with an easy curve to the height of 

 the top water line, in order that the amount of work to be per- 

 formed by the pumping engine may remain constant whether the 

 reservoir be full or empty (a condition necessary to its good per- 

 formance) ; and also to guard against the possible injury which 

 might be caused by the current if a failure in the lower part of 

 the main should occur, and its mouth within tlie reservoir be so 

 placed as to permit the water to re-enter and flow back through 

 it. This latter contingency is to some extent guarded against 



