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THE POPULAR SCIENCE MONTHLY. 



the orifice of the trap into the waste-pipe, as sliown by arrows in 

 the sketch of a pot-trap (Fig. 3). It was observed, too, that a part 

 of the water struck the top of the trap and was reflected back in 

 the form of spray. This suggested the possibility of retaining 

 the water in the trap under siphonic disturbance by repeated 

 deflections from reflecting surfaces. Various experimental pat- 

 terns of traps were made by Mr. Putnam, as shown in Figs. 4 and 

 5 ; and, finally, the form shown in Fig. 6 was found to be anti- 

 sijjhonic and self-cleansing under all conditions that exist in good 

 plumbing practice. It has four reflecting surfaces to deflect the 

 water from the outlet, and the seal is so deep and the construc- 

 tion such as to enable it to resist both evaporation and capillary 

 attraction. 



The general principle that all plumbing fixtures shall act as 

 flush-pots, so that the waste-pipes shall be automatically cleansed, 

 is of great importance. A strong flushing action is secured by 

 making the outlets of the fixtures as large as the waste-pipes 



Pig 7.— a Basin, showing the Proper Form op Overflow-Pipe for atx Lavatory Fixtures, 

 AND THE Arrangement of Outlet and Trap to give Thorough Flushing to Waste-Pipes. 



themselves, and by the use of traps having a free water-way, with 

 no balls or mechanical valves to obstruct the flow of waste- water. 

 Aeration is effected by the admission of a free admixture of air 

 into the waste-pipes, automatically forced in by the water escap- 

 ing from the fixtures above. 



The abolition of inaccessible filth-collecting recesses in modern 

 plumbing has necessitated a complete change in the construction 

 of the old forms of appliances with which we have been familiar. 



