president's address— section h. 163 



of Melbourne by one of the most eminent of the English 

 Sanitary Engineers, Mr. Manserg, M. Inst. C.E., who is 

 also a Member of the Council. Mr. Manserg proposes the 

 partially separate system, and to admit rain-water from the 

 l3ack roofs and yards of houses ; also to pump the sewage at 

 two separate stations to a sewage farm. He proposes several 

 very large sewers — two are about 14 feet in diameter, and 

 these converge into another, which on the same basis would 

 require to be about 20 feet in diameter. Several of the 

 sewers are proposed to be laid at gradients which are not 

 steep enough to render them self-cleansing with the dry 

 weather flow, especially when the system would first come 

 into operation. 



A critique on Mr. Manserg's Report has been published 

 by Mr, Shone, in which it is attempted to prove that Mr. 

 Manserg's scheme is unsatisfactory, and that Melbourne 

 could be much better drained on the Shone System. I 

 recommend all those interested in the subject to study the 

 reports. Having in view the difiiculties of obtaining good 

 natural gradients in Melbourne, and the fact that the present 

 surface drains discharge surface waters as well as the liquid 

 household wastes, it appears to me that the storm-water might 

 have been excluded to a much greater extent than proposed 

 by Mr. Manserg, resulting in smaller sewers. The present 

 surface drains would be suitable for discharging surface 

 waters freed of household wastes, and probably Shone's 

 System might be found most economical in overcoming the 

 difficulties with regard to natural gradients where they exist. 

 It would be easier to flush and ventilate the smaller sewers 

 and maintain them in a better sanitary condition. There is 

 no doubt in my mind as to the partially separate system being 

 as good as the entirely separate system where good natural 

 gradients are obtainable ; but I consider it desirable to point 

 out a few of the advantages of the sejDarate system, as applied 

 in the first place at Memphis, and afterwards in about 30 

 American towns, I will quote the remarks made by Sir 

 R. Rawlinson on the sewerage of Memphis. He says that 

 " the sewers were so small and so well filled by the flow 

 of sewage, that there is very little exposed wall-surface for 

 bacteria to germinate, and very little space for storing up 

 germ-laden air. The gases and heat of decomposition, which 

 so powerfully stimulate organic life, are prevented by the 

 daily flushing which is only possible in small sewers. The 

 smooth glazed surface of the pipes is unfavourable soil for 



