evaporation from traps. This will do no harm if fixtures are in constant use. On the other hand, if special antisyphoning traps are used, and back vents are dispensed with, there will be little circulation of purifying outer air through the waste pipes.

General Features.-Corners and recesses within the pipes and plumbing fixtures should be avoided. All interior surfaces should be thoroughly flushed at every rush of water through the pipes, otherwise the animal matter left sticking to the surface will decompose and send off foul gases. On this account the use of "pan closets," and many patterns of traps, should be discontinued. The plumbing fixtures in a house should be as few as possible. Not only is every additional fixture and pipe joint a possible source of danger, but the principal danger from sewer gas arises from rarely used fixtures, from which the water in the traps has evaporated.

The fixtures on the different floors should be arranged so as to have them as nearly in a vertical line as possible, in order to avoid running waste and soil pipes horizontally or with insufficient fall.

The less wood-work around fixtures the better. Not only does the wood itself become foul, but the space within the casing is dark, damp and dirty-a favorable locality for mould and rot, and a breeding place for vermin.

Unwholesome smells, which are attributed to some faulty construction or arrangement in the drainage pipes, often have their origin in these inclosed spaces.

It is not uncommon in summer, when the air is loaded with moisture, to see water accumulate in bead-like drops on the surface of plumbing fixtures or pipes which are kept cool by a current of water from a tap, and course downward almost in streams. If the fixtures are not inclosed they can be readily wiped dry. If inclosed they receive no attention,

and the accumulation of dirt and moisture becomes very offensive.

The better kinds of water closets are made so as to require no wood surrounding them, except a cover. A very good way to fit up wash stands is to support the slab upon brackets fastened to the wall, leaving the under side entirely open, and the pipes, traps, etc., entirely exposed, or partially hid by a narrow slab placed edgewise under the shelf proper, and extending downward about six inches.

So far as possible it is preferable to have soil, waste and ventilating pipes exposed, to having them inclosed within partitions where they are inaccessible either for inspection or repair.

This method of arrangement is not without its influence on the plumber. He is not less inclined to pour lead joints properly, or to thoroughly caulk them all around, or to make neat and perfect wiped joints, than when he knows that the carpenter or plasterer will cover his work within a few hours. The average house owner will look upon this arrangement as decidedly lacking in finish and not in harmony with interior decorations. Neither is a stove pipe, a furnace register, a steam radiator, or a gas fixture. This is largely a matter of education, and possibly we have been wrongly taught. It is not customary, however, to place these fixtures in rooms where any exceptions can be taken to this method of arrangement.

The common practice of placing water closets and other plumbing fixtures in dark, ill-ventilated places, such as inside rooms, dark closets, under stairways, etc., is wrong in every way. All plumbing fixtures and pipes should as far as possible, be kept open to the air and light. The places which are naturally the most foul stand most in need of sunlight and pure air.

Where it is possible to avoid it, no plumbing fixtures should be placed in a bedroom. During the night some

decomposition will be going on above the trap in any fixture, and some foul gas will be given off. This, with the chance of sewer gas coming in through some defective joint, pipe or trap makes the risk too great to be taken if it can be avoided. They should be confined to the bath room, where special means of ventilation can be employed, and to the kitchen laundry and similar rooms.

A

A multiplicity of fixtures should be discouraged, fixture rarely used is a greater source of danger than one used frequently.

Particular care should be used in arranging the ventilation of a building, so that the air currents tend to pass outward from the group of rooms containing plumbing fixtures, fresh air being admitted to other portions of the building. The facility with which this can be accomplished, and also the proper grouping of fixtures and simplicity of the system of pipes will depend largely upon the architect.

The ornamentation of porcelain ware and of surrounding wood-work by raised or carved patterns is positively detrimental. A perfectly plain, smooth impervious surface is more conducive to cleanliness.

Everything connected with house drainage and plumbing should be of the best material and most thorough workmanship. The best plumbing is not too good. By best plumbing is not meant the most showy, or necessarily the most expensive. Water closets and sinks are not the most appropriate places for gilt and tinsel. On the other hand, it is poor economy to risk health and life on cheap, bad work in the sanitary arrangements in our homes.

When the soil, ventilating and waste pipes are all in position, and before the fixtures are put in place, a test of the thoroughness of the work should be made. This can be done in a variety of ways. The following will be a very good test: Close up the main drain where the iron pipe terminates outside the house wall, also the exposed ends of all

pipes where fixtures are to be connected, and the fresh air inlet, if there is any. The ends of lead pipes should be left somewhat longer than necessary, so that this can be conveniently done by flattening them and closing with solder.

When all openings in the entire system of soil, waste and ventilating pipes are tightly closed below, fill the entire system with water from above nearly to the top, and mark the height at which the water stands. If no leakage is apparent and the water stands at the same level for some hours, the joints may be considered good. The entire work should be carefully inspected while under pressure, and joints re-caulked where necessary.

It is not proper to connect waste pipes from refrigerators or safes, or overflow pipes from water tanks or cisterns directly with the sewers or waste pipes. The discharge from these can be often collected at a common receptacle, however, which is isolated from the sewers by special

means.

CHAPTER XII.

COST AND ASSESSMENTS.

Comparative Cost of the Separate and Combined Systems. No general comparison of the economy of the Separate and Combined Systems of sewerage can be made. It depends in all cases on the condition of each problem, and the relative economy in a particular case can be determined only by a competent engineer, after thoroughly considering the requirements to be met.

As indicated in a previous chapter, there can be no question as to which system will secure the most perfect and sanitary house drainage, whatever the conditions may be. In the Separate System proper we are seeking this with at single aim, and may adopt anything conducive to it and reject anything detrimental to it. How far we may depart from this line from considerations of apparent economy is a serious question.

It must not be forgotten that we are establishing a complete system of subterranean communication between the dwellings of all classes of society, interposing but a small volume of water as a barrier to the circulation of air currents, and when street water is admitted we are introducing another element of danger.

In many of the smaller cities of the United States (and they are comparatively numerous, as shown in Table II) there can be no question as to the superior advantages of the Separate System in economy, efficiency, and adaptability to all the requirements to be met. In cities of this class it is folly to construct a Combined System ill adapted to the work in hand. The question of relative cost, though favoring the Separate System, is, therefore, not a pertinent one.