240 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



sewers of Front Street — West and East — join here in the outlet 

 pipe. 



Fig. III. shows a plan of the same. 



Fig. IV. is a check valve to be placed in the branches to prevent 

 regurgitation when the flush is on. It is so constructed that it 

 always remains open and offers no obstruction to the How of sewage 

 towards the outlet, but when the pressure comes in the opposite 

 direction it closes. Their position is indicated in the map, at letter 

 a, a. The several outlets indicated on the map by b, b, b, b will be 

 referred to later on. 



I wish now to call your attention to the capacity of the system 

 and show how it will be able to meet the requirements of the city 

 when it contains 1,000,000 people. A five foot sewer on Front 

 Street West, running | full would deliver 32,000,000 gals, per day; 

 allow I as much for the East of the Don, 8,000,000. Then supposing 

 the tank fills every 15 minutes, it will deliver 2,000,000 per hour, 

 equal to 48,000,000 per day, making a total of 88,000,000 gals. 

 This is a very liberal allowance, being 88 gal. per head. The Watex*- 

 works will have to wake up before that time comes. 



I come now to the consideration of that part of the subject that 

 has exercised men's minds perhaps more than anything else, namely, 

 the contamination of the city's water supply by allowing the crude 

 sewage to discharge into the Lake. I think that I can show that 

 such a fear is quite groundless. Prof. Laut Carpenter says in his 

 communication with our Mayor and the Board of Health as follows : 

 " With much that has been said both in Chemical and Engineering 

 reports on the self-purification of water, first by discharge into 

 running water of some miles in length and shallow, and second by 

 discharge into a large volume of water containing oxygen I am 

 disposed to agree. I know of many cases in which the first is relied 

 on, for example the Thames (England) I'eceives the sewage of many 

 towns on its banks, such as Reading, Windsor, etc. And yet the 

 water drawn lower down the river for supplying the City of London 

 still passes the test very well. London is considered a healthy city." 



During the past summer I visited several American cities for the 



