150 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VOL. II. 



not to wait upon the " tardy favors of the moon." By adjusting the 

 size of our tank, and extending our high-level sewer to the west and 

 thus intercepting more sewage, we can determine the time of filling the 

 tank as we choose, to one hour or less or more. Thus by intercepting 

 4,000,000 gallons per day, and making the tank to hold half a million 

 gallons, we would have a discharge every three hours, equal to eight 

 tides in the day ; even Jupiter with its four moons could not do much 

 better than that. But if we chose, we could have a discharge every hour 

 or every half hour. 



Then another feature, considerably emphasized, is a rapid discharge ; 

 having 32 feet of head, our discharge would be nearly double as rapid 

 as theirs. 



Not having to provide storage for the whole city for 12 hours, say six 

 million gallons, we only need to provide capacity for half a million. By 

 a simple contrivance of automatic flushing apparatus we save the attend- 

 ance of even a single man. Then last, but not least, we save all the 

 expense and nuisance of pumping. It may be egotism, gentlemen, but 

 I consider I have made a tolerably good substitute for the tides. 



But there is one further merit which I claim for my system that 1 

 have not yet laid before the public. You are aware that I contemplate 

 an outfall pipe of steel 6 feet in diameter, conveying the sewage out to 

 a depth of 33 feet of water. I recommend several openings along the 

 pipe near the outlet to be used alternately. This would give a better 

 distribution and prevent accumulations of solids. Again, as the sewage 

 would be discharged at intervals with great force, it would prevent a 

 deposit of the solids around the mouth of the outlet. And even between 

 the intervals of flushing, while the sewage of the low-level sewer would 

 be passing slowly out of the outlet-pipe there would be no deposit 

 around the mouth. As at such time the motion would be so slow as to 

 allow a deposit to take place in the pipe, only the comparatively 

 clear effluent would flow out, leaving the solids along the bottom of the 

 pipe until the next rush would take place, when half a million gallons 

 sweeping along at the rate of 6 feet per second would again scour the 

 pipe and carry the solids far beyond the end of the outfall. 



Mr. Crimp recommends the adoption of the gravity schemes where 

 possible, notwithstanding the greater initial expense. He also is in 

 favor of provision being made for flushing all sewers of insufficient fall. 



He also describes a very ingenious precipitating tank in use at Dort- 

 mund, Germany, and also Mr. Webster's treatment of sewage by means 



