58 



then great injury and inconvenience may result, and tlie conse- 

 quences to the public health may be most serious. At the lower 

 end of every house drain what is called a disconnector trap 

 will be fixed ; this luill prevent any passage upwards of any gas 

 Jroni the sewer ^ whilst at the same time it will admit air to the 

 drain. At the upper end of every drain a ventilating shaft 

 will be placed leading from a second disconnector trap, which 

 receives sinkwater and excreta from closets ; and various other 

 descriptions are given on the same principle, and in conclusion 

 adds : — It is believed that the best method of constructing 

 house drains has now beeii clearly indicated, and if the prin- 

 ciples pointed out be faithfully adhered to, Adelaide will 

 rejoice in the reputation of being the only city in Australia, 

 and one of the few cities of the world, which possesses a perfect 

 system of house drainage." 



In the system adopted by these regulations they are, in my 

 opinion, trapped once too much, causing unnecessary outlay on 

 the part of householders, and I venture to assert will not be 

 effective in their results as a sanitary scheme. Small-bore 

 pipes are all very well in calculation ; they will dispose of so 

 much sewage according to their inclinations, but in practice 

 they very soon lose their diameter by furring or corrosion, 

 thereby becoming too small to perform their office, however 

 carefully they may have been laid. The cases of stoppage at 

 the first disconnector from the sewer have been numerous, and 

 there is always liability for such to occur by the very con- 

 struction of the trap. It is also designed to prevent the passage 

 towards the dwelling of any gas from the sewer, consequently 

 we have this noxious sewer gas thrown back into tlie main 

 sewer, and delivered at the street level. 



III. — The STSTE:\r as Suggested tbt the Author 

 From the various complaints which have been made by the 

 citizens, we are aware that sewer gas is generated on the line 

 of our sewers, which is felt in the summer to be most objection- 

 able, though we are at once met with the statement that this 

 will not occur when the system is complete. Even when the 

 present system is complete, in my opinion smells will always 

 arise at the surface, either in centre of streets or the more 

 objectionable part at our boundaries. The ventilation of the 

 sewers is undoubtedly insufficient. It is now settled beyond 

 doubt that sewer gas will pass water seals in every kind of 

 trap, therefore the sewer gas which cannot get away will in a 

 few hours normally break the seal at the first disconnector 

 trap, and find its way inside the boundary line upwards, par- 

 ticularly when the position of the outlet of these traps stands 

 higher than the crown of the road. 



