Probably no other plumbing fixture or device has passed through such great changes and been brought from a most unsanitary condition to a condition of such high excellence as the water closet.

A volume might be written on the changes that have been wrought in its construction, but as this work is designed to deal only with present-day plumbing, only those fixtures now actually in use will be considered.

A water closet to be sanitary should possess the following features: It should be protected by means of a trap within itself, this trap having a good seal; there should be as small an area of surface exposed to contact with soil as possible, and all such surfaces should be thoroughly scoured; the flushing of the fixture should be accomplished as noiselessly as possible, and without unnecessary waste of water; the trap seal should be exposed to view; no mechanical devices should be employed in the operation of the fixture, with the exception of the flush tank; and for flushing the fixture it should never be directly connected to the water-supply system.

Plate XVII. Water Closets - Floor Connections

Water Closets & Floor Plate 17.

Connections

Fig A.

Fig B.

Fig. c.

fig. D.

Fig. F.

Modern water closets are superior to the old-style water closets of the pan, valve, and plunger styles in every respect. They avoid dead ends that are neither provided with water nor with ventilation; surfaces between the bowl and its trap, that in the old fixtures were protected in no way, are now submerged; the modern water closet is provided also with better ventilation, a stronger flush, is more noiseless, and is far more cleanly.

The leading forms of water closets now in use are the washout, washdown, siphon, and siphon-jet, the two first named being used very extensively in many cities on the cheaper class of work.

Since the principle of siphonic action has been applied to the water closet, however, the siphon and siphon-jet fixtures have taken the precedence over all other forms, and it appears to be only a matter of time before they will supplant the less satisfactory forms entirely.

The four water closets mentioned above are illustrated in Plate 17, Fig. A showing the washout style, Fig. B the washdown, Fig. C the siphon, and Fig. D the siphon-jet.

The washout water closet is somewhat different from other forms, from the fact that soil, as it enters the fixture, falls into a shallow pool of water above the trap, from which it must be conveyed by the flush into and out of the trap. The meeting of the flush with the resistance above the trap and with the resistance which the soil presents, impedes its force to a great extent, with the result that the water merely runs over the dip into the trap without much force, losing thereby much of the scouring effect that it would otherwise have.

So much of the energy of the flush is used up in removing the soil from the upper shallow bowl that it has not sufficient energy to perform the work needed in driving out the contents of the trap. This same loss of force is to be observed in the flushing of the old pressure closet, in which the flush is sent around the bowl. There is one advantage that is not often considered that the washout water closet has in having its upper shallow pool. The location of the pool allows excreta to remain in sight, which, in the case of the sick room, is often desirable to the physician and nurse. For this reason the washout water closet is sometimes made use of in private infirmaries.

The washdown water closet is an improvement over the washout, as the action of the flush is more severe and its scouring qualities therefore better.

Surfaces, which in the washout closet are left exposed, in the washdown closet are submerged, making the latter much the more cleanly of the two.

At length, however, the principle of siphonage was applied to the action of the washdown water closet, this step marking a very great advance in water-closet construction.

In the washdown-siphon water closet, the outlet is through a horizontal leg, which is contracted so that its area is considerably less than that of the passage above it. As the flush enters the fixture, and the contents of the trap pass out through the vertical passage, the water in passing through this passage attains a much higher velocity than it has when it reaches the contracted horizontal leg. The outflow being thus retarded, the water completely fills the horizontal leg, and as it passes out creates a vacuum behind it.

With nothing but the water in the trap to resist it, atmospheric pressure exerted on the upper surface of the trap seal, forces the contents of the trap out through the outlet and into the drainage system.

Atmospheric pressure is approximately 14.7 lbs. per square inch, and it is this amount of pressure that acts to force the contents of the water-closet trap. When the siphon finally breaks, enough water fills into the bowl to fill the trap, when it is ready for another operation.

The application of the principle of the siphon to the washdown water closet allows a larger amount of the surface of the bowl to be submerged than possible to obtain in the same form of closet in which sole dependence is made on a rush of water to operate it. In the siphon closet there is not only a pushing force exerted by the water entering the fixture, but there is also the force of suction pulling the contents of the trap out of the fixture.

The next step in advance in water-closet construction was the application of the water jet to the siphon closet, as seen in Fig. D.

In the washdown-siphon water closet the formation of siphonic action depends entirely upon the filling of the outlet, and until enough water flows out of the trap to accomplish this the action does not take place.

In the case of the siphon-jet water closet, additional aid is pro-vided for the complete filling of the water closet outlet.

At the point where the flush enters the fixture, it divides, a part entering the bowl through the flushing rim, the rest entering a small passage which leads into the trap in such a way that its opening shall point directly up the middle arm of the trap, from which it emerges in the form of a jet. The force with which this jet emerges will help to raise the water and cause it to pass over into the vertical arm. The aid obtained from this jet, in addition to the natural flow of the contents of the trap into the contracted horizontal leg, quickly forms a solid plug of water, a vacuum forms, and siphonage takes place, as seen above.

This entire action is very strong, and in the case of both fixtures shown in Figs. C and D, all surfaces are thoroughly flushed. These excellent features make of these two fixtures the most sanitary and most satisfactory water closets on the market. In addition, there is less annoyance from the noise created by flushing the siphon water closet than others.

The washout water closet, with its shallow seal and its surfaces exposed to the contact of the soil, may be procured at far less cost than the siphon jet, and it may be said that this fact is the only one that makes its use favored by anyone who is at all acquainted with the subject. The washdown-siphon water closet may be obtained at a slight advance over the cost of the washout, the difference being so slight that it would seem that no one desiring proper sanitary conditions would hesitate a second in selecting the siphon closet.

The siphon form of water closet is the only one that should be used in connection with the low tank, the reason for this being that, although the flush inlet from the tank is enlarged to make up for the loss in head which is secured in the high tank, enough water cannot be thrown into the closet from the low tank to make the flushing of the fixture sufficiently strong.

By the aid of the siphon, however, the low tank is able to produce excellent results.

There are numerous other water closets, working on slightly different construction than those shown in Plate 17, which will hardly be worth considering, as those already discussed are most generally in use. The hopper and trap form of water closet, in its various forms, appears, in comparison to the modern high-grade fixture, to be of a very primitive character, and is now generally prohibited.

The use of the offset water closet is a practice which should never be allowed. This form of closet is made for use in connection with the lead or iron trap used with the pan, pressure, long hopper, and other closets.

Very often, when closets of this class were taken out, instead of taking out the trap beneath the floor, it would be allowed to remain, and the offset water closet, which has no trap, set in place of the old fixture. The reason that one of the modern closets could not be used instead of the offset closet was that there would then be two traps on the same fixture. The objections to the use of the offset water closet are that the flush loses its force before it reaches the trap, consequently not flushing the trap to any extent, and that there is a large amount of polluted surface, extending from the crockery into the trap below the floor, which gives off foul and unsanitary odors into the room in which the fixture is located. The offset closet is made in such a manner as to deceive those not acquainted with the subject into the belief that it is a fixture built on modern principles.

The only course to pursue in renewing such work as the above, is to tear out the trap under the floor, replace it with a lead bend, and use a modern type of water closet.

Vitreous chinaware is now used in the construction of all firstclass water closets. This ware is formed of compact material, which is subjected to a high heat before being glazed. In the employment of this material there is no danger from the cracking or "crazing" of the glazed surfaces. In former times, before modern processes were employed, the crazing of the water closet was of frequent occurrence, resulting in the absorption of moisture by the exposed surfaces under the glazing, the fixture in time becoming foul and very unsanitary.

All water closets, as well as lip urinals and slop sinks, should have flushing rims, so as to flush the entire surface of the crockery.

Water closets should never be located in dark or unventilated places, and the practice of installing them in cellars, although followed to considerable extent, is not a wise proceeding. Sunlight and air are two powerful purifying agents, and when fixtures such as water closets and urinals are placed where ventilation is not provided and sunlight cannot enter, the conditions must necessarily become unsanitary, and the place where the fixtures are located filled with impure air. For this same reason the open plumbing of the present day is much more sanitary and much more wholesome than the old-style boxed-in plumbing.