ANNIVERSARY ADDRESS. 19 



the Railway Construction Branch of the Department of Public 

 Works was providing an extensive electrical plant at the Rush- 

 cutter's Bay Power House for the Rose Bay tramway, it was 

 arranged to obtain the required power from the same source. The 

 lifting plant is practically automatic, the motors being stopped 

 and started as the air pressure varies. 



The question of dealing with other larger and more important 

 low lying levels has also been considered and the relative merits 

 of the Shone system, hydraulic power and pumps driven by 

 electric motors fully investigated. The Railway Commissioners 

 undertook to' supply what electrical power was required from the 

 Pyrmont Power Station at one penny per Board of Trade unit, 

 and at this cheap rate the conclusion arrived at was that from 

 every point of view electrical power would be preferable. 



From the calculations made it would appear that the relative 

 cost per effective horse power hour would be as follows : — Electri- 

 cally driven pumps l*84d.; hydraulic system 185d.; compressed 

 air 2*16d. 



Sydney can claim to be the first city where electricity has been 

 adopted for raising sewage. There will be nineteen stations, all 

 controlled from the central station at Darling Harbour, the level 

 of the water in the pump wells will be automatically signalled, so 

 that the attendant at the head station will know when to stop 

 and start the pumps. 



Telegraphs and Telephones. — Mr. P. B. Walker, Engineer-in- 

 Chief to the Telegraph Department, informs me that the most 

 important construction work carried out by the Postal and Electric 

 Telegraph Department in the city during the past twelve months, 

 has no doubt been the extension of the underground tunnels and 

 the laying of telegraph and telephone cables in them, which has 

 already been the means of relieving the streets of a great number 

 of poles and overhead wires. There are four main lines of tunnels 

 branching out from the General Post Office to the north, south, 

 east and west. The longest branch is that to the south, which 



