The 'Dry Catch'
Seeing that moderate dryness and free access of air are essential for humification, it becomes necessary so to construct our receptacle that these ends may be attained.
This end is not attained in an ordinary pail, because all the urine is retained; there is an excess of moisture, and the mixture becomes putrid and sloppy, unmanageable and offensive.
The best method of treating excreta is to allow them to be deposited in the 'dry catch,' suggested by Mr. Richardson, of Clifton (see fig. [16]). In this arrangement the seat is raised on two or three steps, and the excreta are caught on a slightly sloping concrete floor; the excreta are freely exposed to the air, and the urine flows away down the slight slope and is caught by an absorbent material, of which the best is garden humus.
With this arrangement no putrefaction takes place. It is not a matter of much practical moment whether or not earth be thrown into the dry catch after the excreta, because the arrangement ensures that offensiveness is reduced to a minimum.
If earth be used this humification will go on in the catch itself, and the longer such a catch is used the better it will act, always provided that moderate dryness and free access of air are ensured.
I speak with great confidence as to the success of this arrangement, and with an experience of some years' standing. With a dry catch of this kind used, let us suppose, for the lowest class of property and with daily removal of the excreta, the bulk and weight of the excreta are reduced to a minimum; there is no sloppiness or putrefaction. Collection and transport are easy, and the work is, with suitable tools, not repulsive. If we adopt the estimate of Parkes, that the solid excreta average for both sexes and all ages not more than 2½ ounces per diem, then the household of five persons would provide considerably less than 1 lb. weight per diem.
Fig. 16.—Section of 'Dry-Catch' Privy, with Gutter filled with Absorbent Material to absorb Excess of Urine.