To write a history of traps is quite beyond the author's purpose, but the subject is so important that it cannot be passed over in silence. To describe all that are in the market would only weary the reader. A great many makers would be delighted to see their goods mentioned, while others would be vexed and disappointed at theirs being omitted. Neither of these considerations affect the writer, who is neither a patentee nor manufacturer. The various traps used for the purpose of receiving surface-water and waste-water from sinks, etc, may be divided into the following heads: The cesspool-trap, as shown by Figure 211; mechanical traps, or those with a flap-valve either in the water, in the body of the trap, or on the outlet or discharging end; traps with floating balls, or those with heavy balls, which, under certain conditions, close the trap from back pressure from the drains or sewers; and traps which are constructed so as to retain water in such a way that under ordinary conditions no drain-air can escape through them. This last description can be further divided into two classes: Those (mis)called self-cleansing, and those specially constructed to retain certain matters which would do harm if allowed to pass into the drains. A further class may be added - those which have a water-seal, but are so very peculiar in their construction that they may be said to be almost as offensive as the evils they are supposed to remedy. Anyone who wishes to make a study of the various kinds of traps in the market is referred to the advertisement pages of almost any paper devoted to sanitary or building matters, where he will find plenty to interest him.

Figure 211.

Figure 211 is a section of a cesspool-crap as usually fixed under a scullery-sink, and it would not be an exaggeration to say that more than half of the houses in the most aristocratic squares and streets in London are as shown. In fact, in some of the larger houses these traps are made bigger in proportion - no doubt so as to be in keeping with the house. No matter how large this trap may be made, sooner or later it will require to be cleaned out. The accumulated fat, which will be found to form a crust on the top, and a quantity of other matter, such as sand that gets washed down when the copper cooking utensils are scoured, mud from vegetables, small pieces of meat, bones, etc, from the dinner-plates, and very often portions of garbage and cleanings from game and other kinds of food - all pass into this trap. If any difficulty arises in this, the bell can be lifted off the trap in the sink and the poker will do the rest. When these places are opened for cleaning out, the stench that escapes is so strong that words can scarcely be found strong enough to describe it. More often than not the bell is left off the trap in the sink, so that the trap below may be said to breathe into the house, as the air is rarefied and cooled by alternate discharges of hot and cold water down the waste-pipe. The bell-trap, which is generally placed in the floor to keep the smell of the trap below from escaping, is very often found uncovered or without water. In some cases, where the servants have been particularly clean, and prided themselves on the clean and white appearance of the stone floor, the grating has been so covered with hearthstone that its presence could not be discovered. Everything about this arrangement of the scullery-sink is wrong. There are very few houses indeed that have not a back yard of some kind or other, where the trap could be placed to receive the scullery waste-water, so there is no (or very rarely any) excuse for fixing them indoors. The bell-trap in the sink is a continual source of annoyance and trouble. The water-seal is so little that a slight puff of air will blow through it; in a few hours the water will evaporate out of it. The water-way through it is so reduced in area that it is difficult to get water to run away without lifting the bell, this very rarely being replaced in a proper manner. The bell-trap in the floor is perfectly useless. It is generally placed there to receive surface-water when the floor is washed down with water and broom. As a matter of fact this is never done, the maids usually doing this part of the work on their knees with pail and flannel. Neither is it a good plan to swill down the floors inside a house. It may clean them, but it makes them and the walls for some inches up so wet that it may take several days to make them dry again; or, if any woodwork gets wetted, rot is engendered. So this floor-trap should be entirely removed.

Scullery-sink traps require to be specially made so as to intercept and retain all grease, or sand, etc, as these matters frequently cause stoppages in the drains. This is the reason, it may be presumed, that the old cesspool-trap has still a great many admirers. An improved way of constructing these places is shown in Figure 212. This was designed by a master plumber under whom the writer was working some years ago, and since then a great many have been made on the same lines. The advantages are that this trap can be easily cleaned out without allowing sewer-air to pass through during the time it is open. The incoming water is discharged below the floating matter, so that if this water is hot it does not remelt the grease, or break it up. The outlet is so arranged that grease cannot float into the drain, and this is the great object sought. The trap itself is a small brick chamber, built water-tight, the inside face rendered with cement trowelled up to a smooth surface. The incoming pipe is the lead waste pipe from the scullery-sink continued to within a few inches of the bottom. At A is a brass screw-cap soldered in. On removing this a cane can be passed through the pipe on each side. The outlet has a lead pipe bend fixed to the drain with a lead collar soldered on to fit into the drain pipe socket, so that an air-tight joint can be made with cement. On this bend, as shown at B, a large brass screw-cap is soldered, so that drain-rods, with a hoe or brush on the end, can be passed into the drain to remove any matter that may accumulate there to form an obstruction. The cover for this trap should be air-tight.

Figure 212.