346 PROCEEDINGS OF THE SECTIONS. 
s sometimes attains a power as to burst through the water 
seal, therefore most modern traps are fitted with a junction for a 
ventilating pipe, which offers an easier outlet for the gas than that 
b ‘ 
os iat deal of trouble should be taken in laving a pipe under 
a house floor upon sound foundation in such a manner that the 
ound will not sink under it, as any settlement in the pipes would 
crack or displace the joint, and thereby release both sewage and 
sewer gas under the floor. 
Flaptraps have been largely used to peereny pa sei of gas 
and storm-water up the house drain, but t tri e has proved 
useless after a little use, dirt, paper, sticks, straw, ‘bot &e., 
getting between the lid and the 
This form of trap depends aaa nc closeness of its lid for its 
effectiveness. It has therefore given way in point of adaptiveness 
to the water-trap, which has completely superseded it. Its ten- 
dency to become immovable from rust or to wear at the hinges 
renders it unsuitable. Indeed, any movable piece or part in 
sewer apparatus has this objection, as sewage a a sor = corro- 
sive effect, and is largely charged with oritty subst 
With respect to that part of the subject termed the *ventilatial 
of the dwellings,” I have to explain that it has reference only to 
obviating their becoming charged with sewer gas, and not in its 
broadest sense of procuring a free exchange of fresh for vitiated 
air in the chamber, as the title would imply, as that question is 
more than sufficient for a paper in itself. 
There is another feature in connection herewith, viz., the main- 
tenance of the seal in the traps against the tendency of flushes of 
water in the soil-pipe syphoning the water seal out of the trap 5 
but as this is a detail, it is unnecessary to load this paper with the 
consideration of it. 
I shall therefore conclude by summarizing the objects of this. 
paper, and the methods of so doing :— 
(1.) That the Sydney sewers, for want of legislative poe 
8S 
that legislative power should be obtained enabling the 
City Council to insist on affixing upcast ventilating pipes 
to the walls of any houses, where it m ay be found advan- 
tageous so to do, for the purpose of conducting the sewer 
air to the summit of such houses, and there to discharge 
it in such a position that it will not again mix with t 
breathing-air of the citizens. This pipe would not be 
more unsightly if in front of a house than the rain-water 
pipes. 
(2. ) te owing to the defective manner in which co onnecting 
pipes from the city sewers into the dwellings have in 
