Experimenting upon this point, I have found that stagnant slops become, as a rule, offensive within 24 hours, even when exposed to the air. Thus I tried the experiment of filtering bedroom slops through a trough filled with stones and provided in the middle of its length with a diaphragm reaching from the top to within an inch of the bottom, and having the outlet only an inch or so below the level of the inlet. This caused stagnation and great foulness, which disappeared immediately the outlet was placed at the lowest level, and stagnation became impossible. Soapy water mixed with urine soon becomes foul if allowed to stagnate in traps, but it has never in my experience been foul if poured upon the earth and allowed to soak away. With a good fall and with the outlets of pipes freely exposed to the air, traps are not necessary, and as all forms of traps are but miniature cesspools, this is a great gain. A trap is never possible in an outside metal pipe because of the fear of frost. The abolition of traps is not only necessary, but a very great gain indeed.
3. Slop-water should run in open gutters, and when it has reached a certain distance from the house it should be allowed to soak away as it runs, and take the line of natural drainage of the locality.
This may be effected by means of
Filtration Gutters
The gutters which I have used, and which have been found to answer in a manner which has far exceeded my expectations, are constructed as follows:—
A trench 2 feet deep and 18 inches wide, and of a length varying with the circumstances, is dug, and filled up with porous material, such as builders' rubbish, old crockery, and tins, stones, &c., &c., to within a few inches of the surface, and upon this rubbish, previously rammed, walls of concrete or honeycomb brickwork are formed, provided with a ledge sufficiently wide to support a perforated tile, the perforations being big enough to admit a large sized knitting-needle, say ⅛ in. in diameter. The porous rubbish reaches to within an inch of the under surface of the tile, and the sides are planted. The gutter may, if necessary, be protected by a grating.
Fig. 26.—Filtration Gutter.