The pail or tub system (Fosses Mobiles) which is employed in Belgium, has for its object the collection of the fæces in a state of purity, without admixture with water, in a clean and odourless condition.
The apparatus for carrying it out consists of—
1. The seat. This consists simply of a soil-pan of stoneware or faïence, without woodwork, the soil-pan merely projecting from the top of the descent pipe. Its borders are furnished with a groove filled with water or sand, into which the raised rim of the lid fits.
2. The connecting pipe. This pipe is straight without a syphon, and joins the descent pipe at the very acute angle of 22°, and is about 4 inches in diameter inside. It is, like the next, made of stoneware, glazed inside.
3. Descent pipe. This is from 6 to 8 inches in internal diameter; it is vertical, and is composed of a series of pipes, connected with each other by dry sand joints, without cements, fixed to the wall by iron bands.
It rests at the ground-floor level on a strong flagstone. Its prolongation through and below this stone consists of a sliding pipe of wrought copper capable of being lengthened or shortened, and solidly fixed to the stone by a cast-iron connector. A sort of circular shallow dish (ecuelle), which can be hung under this last part of the descent pipe, serves at a given moment to shut its lower orifice.
4. Tub (Tonneau). The excremental matters coming down the descent pipe fall into a tub of from 2 to 3 hectolitres (44 to 66 gallons), in a hole in the top of which the lower part of the pipe fits tightly. A cover fitted with a spring serves to shut and lute the tub when it is full. Placed on a stand furnished with wheels, the tub is easily managed.
When filled it is immediately replaced by
another similar contrivance. If the tub is underground, the rails (on which the stand moves) should be placed on an incline, so that the removal and replacement may be easily effected. The underground chamber must be isolated, and the entrance to it placed outside the building. The thorough tarring of the interior of the tub not only preserves the staves, but also partly neutralises the effect of the mephitic gases which the excremental matters discharge.
Ventilation pipe. To prevent the smells and gases which are given off from the mouth of the tub from spreading themselves (in the house) by means of the opening in the privy seat, at the upper extremity of the descent pipe, is fixed a ventilation pipe, which rises above the coping of the roof, and the action of which is increased by means of a vane, or any other contrivance producing the same effect.[156]