59 



Thougli I may be in advance o£ professional practice, I 

 cannot see why such an obstruction as the boundary trap un- 

 doubtedly is should be employed, because the main thing is to 

 have no stoppages; the reason being the conveyance o£ excreta 

 and sewage should be immediate, every particle committed to 

 the entire ramification of the passages being kept in ceaseless 

 motion until it arrives at the final outlet at the farm. Even 

 considering the natural course of ventilation for the sewers, 

 these traps are objectionable, as they do not allow that freedom 

 of air which is absolutely essential for perfect safety. My 

 objections to traps in this position are the uncertainty of their 

 being changed by the flush used at one deposit, and the danger 

 of their simply becoming small cesspools between the house 

 and the sewers. The awkwardness and expense incurred when 

 a stoppage occurs must not be overlooked, as the traps are 

 fixed at from three to ten feet below the ground level, and also, 

 as I have already mentioned, are liable to derangement and 

 overflow. 



It is obviously necessary to discharge the gewer gas as far as 

 possible out of the respired atmosphere, consequently it is 

 wrong in principle to ventilate the sewers into the streets 

 alone ; therefore I would do away with the first disconnector 

 trap, and form a disconnecting chamber between the house and 

 the sewers ventilated by a pipe rising above the eaves of build- 

 ings, so that the noxious gases may mingle freely with the 

 higher strata of the atmosphere and become oxidised by the 

 stratified zones of heat and consequent currents that traverse 

 and intersect it. The ventilating pipes to house connections 

 would have to be fully considered in laying out the drainage 

 in districts, and not indiscriminately carried six feet above the 

 buildings they chanced to be against. The gratings in the 

 streets would then perform their true functions — that of being 

 the inlet of fresh air, and by a free course being provided to 

 the outlet there would not be any foul gases left in the sewers. 

 Under some conditions of the temperature the action will be 

 reversed, and whichever way the air flows we get nearer to 

 uniformity, and consequently arrive at natural laws. No ven- 

 tilating pipes from the drain to surface of ground should be 

 allowed within the boundary of property, as the varj'ing dis- 

 tribution of heat in the system of sewers and the relative 

 temperature of the external atmosphere will inevitably cause 

 an escape of sewer gas. Por the same reason no ventilating 

 pipe should be allowed to deliver at the surface in confined 

 rights-of-way or narrow streets. In the former case the ver- 

 tical ventilating pipe from the chamber would be sufficient to 

 prevent their becoming foul, assisted by the ventilating pipe in 

 connection with the pan, and in the latter cases efficient means 

 should be taken at the head of the pipes for ventilation. 



