METROPOLITAN WATER SUPPLY. 



By Mr. James Manning. 



[Read lefore the Royal Society, 2 September, 1875.] 



Mr. Chairman, — Before the discussion on my last paper com- 

 mences I would request the privilege of annexing a few remarks, 

 the omission of which renders the description of my gravitation 

 scheme incomplete. 



Soine persons may think that the great pressure of 1,000 feet 

 in the proposed fire-mains all over the city to be given as a pro- 

 tection again the spread of fires, and for the purposes of obtaining 

 special water-power, would not compensate for the risk of damage 

 that might be done by possible fractures in the mains, were they 

 made ever so strong in wrought iron, and secure by means of abun- 

 dant stop-valves. I was induced to embody such proposal in my 

 scheme by having ascertained that in Melbourne the water-pressure 

 of only 300 feet from the relieving reservoir from Preston, seven 

 miles from Melbourne, is quite insufficient to afford water power 

 in that city for anything more than for a few hydraulic lifts, &c. 

 I was told there, that they now wanted much higher pressure than 

 they have from their present head of water, and by means of 

 their mains of cast-iron. Hence the reason for my advocacy in 

 this direction for ourselves, whilst my high-gathering scheme 

 gives a complete command of such advantages. 



On the other hand, it may be considered by some that if Sydney 

 was served wholly from the proposed Waverley reservoir of 300 

 feet elevation, we should have exactly the same pressure as they 

 now have in Melbourne, and which is known to be adequate to 

 all ordinary purposes, and is enough to be a fair safeguard against 

 conflagrations, and that then the ordinary mains for serving our 

 city would answer all purposes ; whereas the fire-mains under 

 the very high pressure proposed would require separate and 

 special reticulation of their own. 



Some persons may also consider that as Sydney is soon likely 

 to be served with cheap, coal direct from the southern mines, the 

 special water-power for our city could be more readily dispensed 

 with here than for Melbourne. I trust, therefore, that these are 

 considerations worthy of notice, whether the laying on of a direct 

 fire-main from the bifurcation of the pipes at Cook's River into 

 the city be determined upon or not. 



K 



