HISTORY OF CIVIL ENGINEERING IN NEW SOUTH WALES. 645 



side for regulating tlie supply of sewage over the areas prepared 

 for its reception. The outlet well is provided with a twenty-four 

 inch sluice valve for flushing out syphon, the available head being 

 thirteen feet. The foundations of the inlet and outlet houses are 

 constructed with bluestone and sandstone concrete rendered on 

 the inside with cement mortar. The superstructure consists of 

 red and white bricks with stone dressings. The roofs are formed 

 with wrought-iron principals and purlins, wind-bracing bars, &c., 

 covered with heavy corrugated iron. Provision is made in the 

 inlet house for tlie discharge of storm water over weirs into 

 channels leading directly into the river ; and channels are pro- 

 vided for leading the sewage directly into the river should it ever 

 be found necessary. 



SEWAGE FARM. 



For the purpose of filtering the sewage about three Imndred 

 acres of loose sandy ground were resumed, of which about twenty 

 acres are in course of preparation in sections as required. A series 

 of filter beds have been prepared for the disposal of the surplus water 

 during heavy rainfall, the aggregate area of which is about six 

 acres, and they are capable of filtering four hundred thousand 

 gallons of sewage per acre in twenty -four hours. They are used in 

 rotation, in order tliat the highest filtering power may be obtained. 

 On the ground, sloping towards Cook's River, cultivation areas 

 are laid out in terraces ; each terrace is laid out on the ridge and 

 furrow system, and connected to the main carrier by means of 

 small timber distributing carriers with timber boxes and sluices, 

 the whole system being so arranged that the plots can be flooded 

 or watered as required. The terraces and banks of the main carrier 

 are planted with Mesembryanthemuni tigrinum ; the prepared 

 beds are planted with sorghum, barley, lucerne, Italian I'ye-grass, 

 vegetables of various descriptions, orange and lemon trees. The 

 area under cultivation is about three acres, which is found to be 

 sufficient for the purification of the whole of the sewage at present 

 delivered ; but as the system becomes extended a larger area will 

 be required. The cultivation is so far promising that good results 

 may reasonably be expected in the future. The sanitary result is 

 proved by the high degree of purity of the effluent water as shown 

 by the results of an analysis made by Mr. W. M. Hamlet, the 

 Government Analytical Chemist, which demonstrates the efficacy 

 of atmospheric oxidation, sunlight, and filtration through sand. 



STORM-WATER SEWERS. 



Some extensive works have been carried out for the disposal of 

 storm-waters for the protection of low-lying lands, among which 

 may be mentioned the storm-water channel through Wentworth 

 Park for carrying off" the surplus water discharging into Black- 

 wattle Bay. The sewer is constructed of concrete twelve feet 



