CITY SANITATION AND SEWAGE DISPOSAL. 235 



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

 much less amount than that. 



Now, as Messrs. Herring and Gray propose to have an outlet pipe 

 2,000 feet long and 6 feet in diametei-, running out into the lake, the 

 ■simplest arithmetical calculation will show the velocity with which a 

 given quantity of water will flow through said pipe : — 



12,000,000 per day 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. 



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

 more, Neville, Latham and Knichling that a velocity of 2^, 2^ 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 heavy 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 I'eaches 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 throuorh. 



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

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

 Some of the property owners along the water-front complained and 

 200 feet moi'e 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. McAlpine and Tully'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 



