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pollution will be prevented, and the dwelling cut off from the 

 main sewer. The local pollution that collects about ordinary 

 bell traps and catch pits, is as offensive and injurious to health 

 as the direct flow of sewer gas. Mr. Gray advocated that the 

 open gully just described, should, if possible, be the receptacle 

 for all the drainage of the house, from closet, bath, and scullery, 

 and that, by this means, the seat of the one trap cutting off the 

 town sewer would be always charged, and thereby prevent the 

 return or absorption of sewer gas. The gully should be covered 

 by a moveable open grate which will admit of removal for exam- 

 ination, and will also allow the syphon trap to be cleared in case 

 of obstruction. With this arrangement it would simply im- 

 possible for any injurious sewer gas to return into or about the 

 dwelling, and the open character of the system admits of com- 

 plete supervision and therefore the immediate detection of any 

 local pollution that may collect from carelessness. 



Mr. Gray described the several patented and other devices 

 for accomplishing the same end, but all were more or less 

 defective, or too complicated for practical application, and there- 

 fore he strongly advocated the adoption of his system, which was 

 simple in construction and thoroughly effective in its operation. 



