Page:Popular Science Monthly Volume 33.djvu/323

Rh soil surrounding the foundations is drawn freely into our dwellings, and any pollution of this soil-atmosphere must occasion serious danger.

In a like manner, rain-water conductors are to be cut off from a direct connection with the house drain or sewer. The upper end of conductor-pipes opening near windows may readily convey sewer-air into the house, unless special precautions are taken to guard against it.

It is usual to place a large trap in the main house-drain a short distance outside of the cellar-wall. The object of this is to keep the air of the street-sewer from entering the drain-pipes within the house. But a trap in the main drain obstructs the outward flow of sewage to such an extent as to cause accumulations of filth to collect, which may produce a condition of affairs in the house-drain considerably worse than that existing in the sewer. In ordinary cases it will be safer to omit the trap, and allow the air of the sewer to flow through the main soil-pipe and out at the top above the roof. But there are important exceptions to this general rule. A trap should always be used between a cess-pool and the house draining into it. And when sewers have a slight inclination, with a sluggish flow through them, so that they are unusually foul, it will be better to have traps put into the connecting house-drains. Whenever these traps are used, there must be an inlet provided for the admission of a copious supply of fresh air to the drain-pipes between the trap and the house, and as near to the former as possible. This will cause an almost constant upward flow of air through the main channel of the house drainage system, giving free ventilation to places where impurities may collect.

Space will not allow a more extended consideration of matters of detail. The design and execution of our systems of house drainage should always be intrusted to some competent sanitary authority, in place of being left to the hap-hazard direction of careless architects and ignorant plumbers. The importance of obtaining absolute security where so much inherent danger exists can not be overestimated. With all the advantages derived from a constant and sure development of the science of sanitation, our houses may be made safe against the entrance of sewer-air. The perils arising from ignorance and neglect are easily eliminated. And, above all, a determined effort should be made to arouse public opinion, so that it shall demand the repeal of objectionable municipal ordinances framed in the interest of corrupt politicians and mercenary tradesmen.