3o6 



THE POPULAR SCIENCE MONTHLY. 



opposed to sanitary requirements. Double traps are not permis- 

 sible in any case for a single plumbing fixture, since their use 

 greatly retards the outflow of water and waste matter, thereby 

 causing accumulations of filth that are dangerous and offensive. 

 It should be observed, too, that in these closets the second trap 

 gives no additional protection against sewer-air, since a relief -pipe 

 from the air-space between the traps opens directly into the apart- 

 ment in Avliich the closet is placed through a concealed orifice 

 above the flushing-tank. The main trap is also completely hidden 

 from view in a part of the closet entirely inaccessible. 



Figs. 12 and 13 show a trap-jet closet devised by Mr. J. Pick- 

 ering Putnam to conform 

 to the requirements of the 

 essential principles already 

 stated. Its construction is 

 extremely simple. It has a 

 deep and perfectly protected 

 trap -seal exposed to plain 

 view in the bowl of the 

 closet. The flushing -pipe 

 stands always full of wa- 

 ter, equilibrium being main- 

 tained by atmospheric pres- 

 sure. Should the water in 

 the bowl be lowered by 

 evaporation or siphonage, 

 air will enter the flushing- 

 pipe through one of the 

 opening* at the lower end, 

 and water immediately de- 

 scends to restore the loss to 

 the trap-seal. 



Fig. 14 shows a simple il- 

 lustration of this principle 

 in the sketch of an inverted 

 bottle with the mouth sub- 



FiG. 12.— Showing the Principle of a Tbap-Jet t • -i • j? j. 



Watbr-Closet. For convenience of illustration the EQCrgea lU a DaSlU OI Waier. 



inlet and outlet are here represented on opposite 'pj^g COntcuts of the bottle 

 8ide8 of the bowl. ■ t i i t t 



remain undisturbed so long 

 as the level of the surface of the fluid in the basin is constant ; 

 but if this be lowered, so that air enters the mouth of the bottle, 

 a corresponding volume of water escapes from the bottle into the 

 basin to restore equilibrium. The application of this principle of 

 protection to houses which are closed and left untenanted during 

 several months of the year is manifestly of great importance. 

 Our city residents, after a summer passed at the sea-shore, or in 



