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temperature o£ the outside air would be sufficient to cause a 

 current of air from street gratings, "he said tbat it seemed 

 to him quite clear that the summer air being so much 

 lighter could not fail to replace the cooler or heavier sewer 

 air, whilst m winter the case would be reversed, for the sewer 

 air w^ould then be the warmer. There was no doubt that the 

 tendency for gases to mix and become diffused was an impor- 

 tant consideration, but he thought that in such a case as ven- 

 tilating a large system of drains its action would be too slow 

 to be of much practical utility, something much prompter and 

 more effectual being required. 



Mr. Paekee, C.E., thought that the deep drainage system 

 in Adelaide was at present illusory, because so few of the 

 closets were connected with it. To make it of any use, con- 

 nections should be made complete. He condemned the 

 plan suggested by Mr. Haslam of bringing the sewer air 

 nearer to the house. The great danger in all cases w^as the 

 sewer emanations entering the house. AVith respect to the 

 proposal to take the sewer air b}^ ventilating pipes to the 

 eaves of the houses, or even five or six feet above them, 

 was, he thought, also very objectionable, for there would be a 

 fear of its falling and entering by the bedroom windows, &c. 

 He thought that the present plan of allowing the air to escape 

 at the • street gratings was much safer, as there was a greater 

 chance of its becoming diffused. Before, however, the matter 

 could be fully discussed it would be necessary to collect more 

 data. The size of the sewer j^ipes was said to be small. To- 

 wards evening they would be nearly full of sewage. This 

 would cause a displacement of the air, and serve as a means of 

 ventilating or removing the sewer air daily. It would be 

 necessary to ascertain the relative differences of temperature 

 inside and outside of the sewers, and also as to the direction 

 of the currents of air at the outlets at the street gratings, 

 before the question as to the best method of ventilating the 

 sewers could be profitably discussed. 



Mr. RuTT, C.E., pointed out that all the outlets at the street 

 gratings were not at the same level, hence this would cause a 

 current of air to pass sometimes from an upper level to a lower 

 and Dice versa. It would be necessary to place cowls on the 

 ventilating pipes if they were to produce any effect in causing 

 a ventilation of the drains. 



Mr. PoLLiTZEB, C.E., advocated strongly the plan of flushing 

 drains. He thought that the climatic conditions in Adelaide 

 were highly favourable to the successful carrying out of a 

 system of drainage such as he advocated. It would not only 

 carry off all the refuse, but also sweep out all the sewer air. 

 He said that the system of flushing had been found eminently 



