USE, CONSTRUCTION, AND COST OF SERVICE KESERVOIRS. 149 



however so improved, that very good results are being obtained 

 by the direct pumping system. 



I have inspected many towns in America where this method is 

 adopted in its entirety, and in nearly all cases where it was seen 

 at work the engines were either of the Worthington Duplex 

 Direct Acting type, or what is known in America as the Holly 

 system was adopted. With the Worthington type of engine, so 

 long as the boiler pressure is uniformly maintained, the engines 

 act automatically and keep up a steady and constant pressure in 

 the main, but the use of engines of the Rotative Fly Wheel class 

 is almost inadmissible, as the stored momentum will probably 

 burst a pipe when the mains are full before the engines will be 

 brought up unless an air vessel of very large proportions is in use, 

 but even this is not a certain safeguard. 



I am aware that very sensitive automatic gear, notably the 

 Holly gear, has been introduced for governing such engines by 

 the pressure in the main, but it is complicated, and I have been 

 told by many who have had experience with it, that it is unsatis- 

 factory, and therefore not a desirable apparatus to rely upon for 

 " rough and ready " work such as pumping. 



In towns situated on a plain such as Bourke, Wentworth, &c, 

 the combination of the two systems, viz. — " Reservoir " and 

 " Direct pumping " can be resorted to with great advantage. 

 Owing to the difficulty in constructing very high tanks economi- 

 cally, iron tanks hereinafter described have been adopted and 

 erected at an altitude of about seventy feet, giving a pressure of 

 about thirty pounds (301>s.) through the town, which is sufficient 

 for ordinary domestic use but insufficient for fire extinguishing 

 purposes. 



Should a fire occur, the engineer only has to close the valve 

 leading to the elevated tank and to pump direct into the main ; 

 in this case he may divert his attention from his engine, and 

 devote it wholly to the boiler to keep up an uniform pressure. 

 For instance, at Wentworth, where two sets of Duplex Worthington 

 pumps have been laid down, I carried out a series of tests and 



