water a depth of 20 feet over the whole, but a quantity of rock was left, as the capacity was thought to be sufficient without taking it out. The southern division has 30 feet of water where the bottom was filled in with embankment, and 25 where excavation was made. A portion of rock was left in this division for the same reason as that in the northern division ; the greater part of it being in the south-west corner, where it

rises above top water line.

The capacity of the Reservoir when both divisions are full, is 150,000,000 Imperial gallons. The surface of water in the northern division covers 18.13 acres, and in the southern division, 12.75 acres ; making in both nearly 31 acres. Plate XXIII. is a plan of the Receiving Reservoir. The Aqueduct enters a gate chamber at A. where there are regulating gates by which the water can be discharged into the northern division ; or into the southern division by a continuation of the Aqueduct within the Reservoir bank to the angle B. of that division. A connection pipe of cast iron is placed in the division bank at C. to allow the water to flow from one division into the other in order to equalize the level ; it is placed 10 feet below top water line and has a stop-cock to close or open it.

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At D. is a waste weir, where surplus water may pass off: it is so arranged that the water, when it rises to a proper level, will flow into a well, and from this a brick sewer conducts it off into low grounds, where it finds its way to the