A contrivance for excluding the effluvia arising from drains, etc. The most simple and effectual trap for this purpose consists of what is termed a water joint, which may be variously arranged. Fig. 1 represents the construction commonly adopted for sinks in kitchens, etc. a is the pipe leading to the drain, the upper end passing through the bottom of a small metal cup b, the rim of which rises somewhat higher than the top of the pipe, and is cemented or soldered into the sink. Over the mouth of the pipe is inverted a cup c, somewhat smaller than the other, and descending to___ within a short distance of the bottom of b, and on the top of this is fixed a strainer to prevent the passage of substances which would choke the pipe. Now as the water in passing off by the pipe will always leave the cup b full up to the top of the pipe, the cup c will always be immersed to a certain depth in the water, which will effectually prevent the escape of foul air from the pipe a, for air being lighter than water, cannot of course descend through it.

Fig. 2 represents an air trap, which, instead of being made of metal, is fabricated of the common red pottery, and is particularly adapted for falling into a course of the " flooring quarries," used in many parts of the country, which are cleansed by washing and sluicing them with water. In its superficies it presents a square of 9 inches, the same as the ordinary quarries, a is the grating; b the trap frame. It will be evident no foul air can pass up the grating, as the only passage for it is through the water, over the stop c, and under d.