HiGGiNSON. — Sanitary Seiverage. 377 



in duplicate, in order to guard against the possibility of stop- 

 page from accident. From the dwelling-house to the ejector 

 the sewage flows uninterruptedly, and upon entering the 

 ejector the sewage is practically done with, no back-flow even 

 of gas being possible. The velocity of 2^ffc. per second will 

 convey sewage through a mile of pipes in thirty-five minutes, 

 so that there is no possibility of gas being generated under 

 proper conditions. 



The W'hole apparatus is exceedingly sirnple, and, having 

 few working-parts, is little liable to damage, and costs equally 

 little for repair. The air-valves are constructed of gun-metal, 

 and occupy but a small space. The ball-valves in the inlet and 

 outlet-pipes are of hardwood, and are found to pass substances 

 such as hair, string, &c., which are a constant source of trouble 

 to the valves of pumping-engines. 



One special feature in favour of this system over Mr, 

 Clark's is, that there is no possibility of sea-water finding its 

 way into the main, while with a brick sewer two miles and a 

 third in length, carried to a depth at one end of 9ft. below" 

 high-water mark, the sea-water must find its way in through 

 every crevice and crack in the work. This water has to be 

 pumped out, together with the sewage, at the cost of the rate- 

 payers. 



It will be readily understood that there is considerable diffi- 

 culty in introducing an entirely novel system. Its being based 

 upon scientific principles not thoroughly understood by every 

 one, is quite sufficient to warrant unthinking persons in jump- 

 ing to the conclusion that it is complicated and liable to result 

 in failure ; although the experience of the last few years at 

 numerous places where the system has been adopted has re- 

 sulted in universal satisfaction being given. 



Any improvements in sanitation should become of deep 

 interest to the community ; and that must be my excuse for 

 taking up so much of your time. Many people shut their eyes 

 to all matters relating to the subject, leaving it to others w^hose 

 sphere of life is more intimately connected therewith to work 

 out the problems ; and it is as well, perhaps, that it is so, or 

 the discussion would be endless, and we should never arrive 

 at the stage for action being taken. 



In conclusion, I repeat that were Wellington sewered upon 

 the pneumatic system the sewage would be rapidly, e&'ec- 

 tually, and inodorously conveyed from the city in a sealed 

 iron main to any outfall deemed desirable. In such main 

 there would be neither manholes nor ventilators to annoy the 

 public. By the exclusion of the rainfall the quantity to be 

 dealt with could be accurately determined, so that to convey 

 that quantity the sizes of the sewers and pipes could be pro- 

 perly adjusted. 



