detail all public and private drainage witli confidence and ac- 

 curacy. 



In every system of sewers provision for perfect ventilation 

 must be made, as every cubic foot of fluid admitted vrill dis- 

 place a similar quantity of air. If no provision be made for 

 escape, the air in tbe sewer would be under pressure, and tend 

 to force its way tbrougb every imperfectly trapped inlet wbich 

 may be existing ; and should such inlet be within the house, 

 the atmosphere thereof would be vitiated. 



The means of ventilating the sewers is by small brick 

 chambers placed five or six hundred feet apart, constructed in 

 connection with a manhole at or near the centre of street. The 

 air in escaping passes through a basket of charcoal, and after- 

 wards through an iron grid fixed at the level of street surface, 

 the charcoal rendering the air inodorous. A more active venti- 

 lation has in some cases been attempted by connecting the 

 sewers with a furnace or large chimneys. Undoubtedly a more 

 rapid change of the air of the sewers would thus be effected, 

 as the draught would be promoted by the heated chimney. If 

 any stagnation should occur in the sewers of Adelaide it will 

 be due to errors in construction. 



When there are several branches to the house drains it is 

 desirable to carry them all to one point into a dip trap. If 

 this be done, no further trapping at the junction of the house 

 drain with the public sewer will be required. A direct com- 

 munication from this trap to some convenient wall where a 

 ventilating pipe can be fixed is desirable, as it removes all 

 chance of pressure within the pipes, and ensures a perfect 

 ventilation. If the soil pipe be carried for its full size up to 

 the top of the house, and a syphon trap be fixed at its lower 

 end, the ventilation of the pipe will be perfect, and the danger 

 of gas entering the house reduced to a minimum. 



Such, gentlemen, is the advice the late Mr. Clark gave the 

 citizens of Adelaide in his report. 



II. — The System Ekfoeced by Eegulations. 

 Under the heading of " Descriptive Directions" the regula- 

 tions say : — " The most important part of a system of deep 

 drainage, such as has been carried out in Adelaide, is the estab- 

 lishment of connections between the sewers and dwelling- 

 houses. Upon the manner in which these connections are 

 made, and the care bestowed upon them, will depend in a great 

 measure the success or failure of the whole undertaking. If 

 the connections are properly made avast benefit will have been 

 conferred on the community by the construction of the works, 

 and a considerable improvement in the health of the city may 

 be expected ; if, however, the connection be improperly made, 



