( 32 )
A.-No, because you have so many joints and the surface is rough. Sewage matter sometimes sticks to the comparatively rough sides of the sewers, it gets dry, then wet and afterwards putrifies and becomes offensive.
373.-Is brick better?
A.-Brick rendered in cement is much better.
374. And what about glazed earthenware?
A.-That is better still, but they cannot make the pipes in this material much larger than 24" × 36′′.
By Dr. Manson.
375.-If the gullies are properly trapped and the house drains properly trapped, do you think the system of ventilation by shafts would be sufficient?
A.-I don't think it would be the least use.
376.-Why?
A.
Because the shaft ventilator is too far from the sewers. I may mention the new ventilator above Mr. GOURDIN'S; you can perhaps imagine the great pressure of gas at Greenmount being at the "Dead end" of a big sewer draining a part of China town below. That pressure ought to be relieved.
377.-The pressure will not be more than one atmosphere?
A.-Nothing like that pressure, but as the sewers are constructed the pressure is
considerable.
378.-If there were a pressure it would constantly ascend to the shaft?
A. Yes, but if a sudden rainstorm comes and the water rushes down the sewer, where is all the gas to go to? It does not ascend gradually to the ventilator. It is driven up these defective traps into your houses. If there were a number of ventilators in the streets, the gas would have an opportunity of escaping.
379.-Would not that be very unpleasant?
A.-Not if it were filtered through charcoal. It passes over a number of layers and it is impossible that any smell can escape.
By Dr. Cantlie.
380. Which is the better vegetable or animal charcoal?
A.-Either will do but animal is the best. The gas cannot get out without having
to pass through several layers of this charcoal.
381.-The section of the sewer would be wider than the shaft that goes up the hill,
A. Yes, in the lower part of the town, because as a rule they take in the water from the respective water courses and side channels.
382.-Sewer gas will not go down and then up again?
A.-Not without some artificial means of forcing it down.
No comments yet.
Private notes are available after approval.