110 SOME REMAEKS ON SEWERAGE SYSTEMS. 



A great deal has been claimed by Mr. Shone for his sys- 

 tem which in reality is not due to it, but is held in common 

 by all good gravitation separate systems ; such as the first 

 three advantages I have stated. This has raised prejudice 

 against his apparatus ; but there is no doubt that under 

 certain conditions, when it is impossible to obtain self- 

 cleansing sewers by gravitation only, it is most useful, and 

 in some cases even economical. 



Concentration. 



There is another point in favour of Shone's system of 

 numerous ejectors, in that it is not necessary to collect the 

 sewage at one point. Concentration may be both an evil 

 and an advantage ; but I fear that in most cases it is the 

 former. 



The present experience with the drainage of London, 

 which is emptied into the Thames at two points. Barking 

 and Crossness, is an illustration of the trouble caused by the 

 accumulation at one point of large quantities of putrefying 

 matter. The trouble of dealing with sewage so as to pre- 

 vent a nuisance is at all times great enough ; but it becomes 

 doubly great where one district is made the receptacle for 

 the refuse matter of many others. It may of course be 

 claimed that the other districts are the better off in conse- 

 quence — and so they may be, provided the sewers do not 

 take upon themselves the vocation of ventilating flues, to 

 draw the foul gases from the scape-goat district into those 

 of its more fortunate brethren; but I am of opinion that 

 trouble would often be saved, even if the establishment 

 charges were rather higher, if sewage could be delivered 

 and dealt with at several points instead of at one. 



The city of Berlin, with its population of over 1,000,000, 

 disposes of its sewage by pumping it over several farms 



