132 WATER SUPPLY TO SYDNEY BY GRA.VJTi.TION. 



as shown by the water delivery and water power notes on the 

 face of rny map, and in my late paper, whereby it may be seen 

 that if two pipes of only 24 inches diameter charged at an eleva- 

 tion of 1,062 feet over the sea, and conveying Is, 000,000 gallons 

 of water daily to the Waverley and Petersham heights, including 

 4,000,000 gallons to be sent into Sydney direct under full pressure 

 for fire-mains and engine power, there the hydraulic force that: 

 would be available for machinery at those places, and without the 

 necessary loss of any of the pure water for after-consumption, 

 would be equal to no less than 3,184 h.-p. of incessant action clay 

 and night, and which competent engineers here estimate to be 

 worth no less than £20 per each h.-p. per annum. At this 

 valuation, and if the power was realized to its full extent by 

 capitalists, as is done to a like extent in Freiburg, the income 

 that would be derived from this resource alone would amount fco 

 no less than £63,680 per annum, and this sum reckoned as it 

 were at 5 per cent, interest would represent a vested capital for 

 the country of no less than £1,273,600, which would alone, and 

 without reckoning the value of a delivery of 18,000,000 gallons 

 of pure water into Sydney and suburbs, be more than the probable 

 total cost of the whole of my gravitation scheme, completed from 

 one end to the other, with a full supply of water by the double 

 pipes of 24 inches diameter. 



Finally, I may venture to say that if the Illawarra railway by 

 the direct route becomes a determined fact, and if adequate labour 

 can be obtained, this project of water supply for Sydney by 

 gravitation could be completed in two years from the time the 

 work would be commenced, after George's River had been rendered 

 crossable by the railway, to facilitate the transport of the iron 

 mains and large quantities of Portland cement. 



Discussion. 



The Rev. "W. Scott understood that Mr. Manning proposed 

 to convey the water by continuous mains from a height of over 

 1,000 feet ; and he asked for information as to the power of 

 resisting the enormous pressure on the pipes. If the pipes were 

 12 inches in diameter, the pressure at the lower end of the main 

 would be something like 45,000 lbs. 



Me. Mannino said that the mains would be a series of strength, 

 according to the altitude of pressure. lie had appended to his 

 plan a note to the following effect : — " If two wrought iron or 

 steel mains of only 18 inches diameter, be applied to the high 

 elevation of 1,062 feet at point A, the pressure could be borne 

 with safety, and the velocity of the water delivered would be so 

 great that no less than 4,270,801 gallons with the 850 feet pressure 

 could be delivered daily into a reservoir on the top of the Peter- 

 sham and Canterbury heights by one pipe, and the highest point 



