Such a filter requires to be taken out and the filtering renewed in 6 to 12 months, depending upon the cleanliness of the water catch. With the precautions mentioned above in regard to the care of the roof, such a filter should do good work for one year.
Sanitation
Sanitation.—This heading is intended to embrace the removal and disposal of the various kinds of refuse and waste produced in the dwelling from day to day. Endless volumes have been written on the subject, but in plain words the whole art resolves itself into sound pipes for the conveyance of the fluid portion and efficient ventilation of the receptacles and conduits.
House Drains.—It was pointed out by Burton,[1] before the Society of Arts, that where, as in London, the sewerage system is fairly good, dangers to health arise not from the sewers direct, but either from the sewers by means of the house drains, or even more often from the house drains themselves. It is quite agreed by medical authorities that diseases may arise from gases evolved from the drains, or even discharge pipes in a house, entirely apart from any specific infection such as may be conveyed by means of sewers.
This being the case, it will be seen that the thing which most behoves us is to make sure that the house system is efficiently doing its work. It is evident that the objects to be aimed at in constructing a system of house drainage, are as follows:—
First. All matter placed in any of the sanitary appliances in the house must be carried, with the greatest possible expedition, clear of the premises, leaving behind it as little deposit as possible.
Second. All sewer air must be prevented from entering the houses by the channels which serve to carry away the sewage.
Third. Since it is impossible to have house drains absolutely clean, that is, devoid of all decomposing matter, all air from house drains, and even from sink, bath, and other waste pipes must be kept out of the dwelling-rooms.
To which might be added a fourth, that a constant current of fresh air must be established along every pipe in which it is possible that any decomposing matter may remain, so that such matter may be rapidly oxidised, or rendered innocuous.
The number of houses in which sanitary inspectors find the drainage arrangements to be thoroughly good, and to be fulfilling these conditions, is surprisingly small. In fact, in all the houses they are called upon to examine, except those which have been arranged, within the last dozen years or so, by some engineer, builder, or plumber who has made a special study of the matter, are found defects which interfere with the due fulfilment of one or other of these conditions.