What is meant by a blind vent?

It sometimes happens in the plumbing of houses in places that are not subject to plumbing ordinances and inspection, that unscrupulous workmen will carry the vents from fixtures back to the wall, ending them at this point without connecting them into a main line of vent. They are sometimes left open, and sometimes closed with a rubber packing. Such a vent is called a blind vent, and is of the most unsanitary nature, as through the vent, direct communication with the sewer exists.

How close to the surface of the ground should a leeching cesspool be located?

It should set as close to the surface as possible. The reason for this is that the bacteria which exist in the soil, and the action of which purifies the liquids leeching from the cesspool, exist only within a very few feet of the surface. They depend upon air for life, and as the air does not penetrate sufficiently to lower depths, they cannot live at such levels.

What kind of pipe should be used for drainage underground?

Inside the foundations of buildings nothing but cast iron pipe should be used underground, and outside either cast iron or earthenware pipe.

Wrought iron, even though galvanized, should not be used underground, as it is readily attacked by moisture and various substances contained in the earth, and its length of life is therefore very short.

What is the cause of air-lock?

Air-lock is a frequent trouble on both the drainage and the hot water supply system. On the drainage system it is caused principally by double trapping, under which circumstances the air standing between the two traps prevents the easy passage of waste with the consequent greater liability of stoppage. In the case of hot water supply systems, unless properly piped, air will collect at high points, and seriously effect the circulation.

What section of the drainage system is called the house sewer?

That section of the drainage system which extends through the cellar, into which all soil and waste stacks and branches deliver their waste. The house drain extends just outside the cellar wall, where it connects into the house sewer.

What section of the drainage system is called the house drain?

That section of the drainage piping, usually running from the point where the house drain ends, to the sewer in the street.

In what manner are underground drainage, water and gas pipes seriously effected by electric currents?

The action of electrolysis is essentially the action of the electric battery, which consists of two metallic plates in a saline solution.

As is well known, in the action of the battery, one of the plates constantly wears away. The same action takes place underground in many cases, due principally to the escape of the electric current from electric railway circuits, the pipes in this case representing that metal in the battery which is attacked and destroyed. Generally the electric current of the railway system is carried from the power station through heavy wires, and returns through the tracks. The latter are not insulated or protected in any way, and if the current finds an easier passage through some nearby pipe than through the rail, it will jump from the latter into the pipe, later on returning to the rail again.

Whenever there are two paths for the current, it will divide between them, the greater part of the current taking the path which presents the least resistance. The points where rails come together represent the points of greatest resistance in the rails, and are the points where the most trouble occurs. If the current passed into the pipe and did not have to leave it again, no damage would result to the pipe, but at those points where the current jumps from the pipes back to the track or to some other conductor, the pipe becomes corroded and finally eaten entirely through. No harm results however, at points where the current enters the pipe.