CITY SAXITATIOy AND SEWAGE DISPOSAL. 235 



steam in our many steam-boileus, we shall find that we will have a 

 much less amount than that. 



1^0 w, as Messrs. Herring and Gray propose to hare an outlet pipe 

 2,000 feet lono; and 6 feet in diameter, running out into the lake, the 

 simplest arithmetical calculation will show the velocity wirli which a 

 given quantity of water will flow through said pipe : — 



12,000,000 per dav will give vel. of 9.4 inches per sec. 

 9,000.000 " ' " " 7.0 



8,000,000 " " '■' 6.25 '•' 



This last I consider all we could count on in dry weather for 

 flushing the outlet pipe, viz., 6^ inches per second. 



Xow it was proved beyond any question by such men as Beard- 

 more, Neville, Latham and Knichling that a velocity of 2^, 2i and 3 

 feet per second is necessary to make them self-cleaning. By 

 reference to the table we find that under the most favorable circum- 

 stances, viz., 12,000,000 galls, pei day, we only get a velocity of about 

 ■9 inches per second, or just one-third of what it should be. The 

 inevitable consequence will be that the hea-\y parts of the sewage 

 that have been carried along in the sewers where the fall has been 

 sufficient will immediately begin to subside when it reaches the sub- 

 merged part of the pipe, and where the velocity will be as before 

 stated. I venture to predict that if such a scheme were carried out 

 it would not continue in working order one season through. 



An instance in point has recently occurred at the Orillia Asylum, 

 ■where the sewage emptied into the lake thiough a pipe 200 feet long. 

 Some of the property ownei-s along the water-front complained and 

 200 feet more was added on. The result was a blockade, and the 

 ■pipe had to be opened at the former place. 



Now let us turn to a brighter prospect. I believe I have a 

 sovereign balm for every evil I have pointed out in the foregoing 

 schemes. It consists in attaching a flushing tank arrangement to an 

 intercepting system somewhat similar to Messrs. McAlpiae and Tally's 

 which I shall briefly describe as follows : — 



For the sake of analogy we may compare it to a tree-trunk, its 

 roots and branches. Beginning at the top of the trunk we would 



