the top of the trap nearly to the bottom, so that it completely separates the air in the third compartment from that in the second, and dips beneath the level of the water in the two compartments. The top and sides of this third compartment are made of stoneware, so that it does not communicate with the external air, the outlet to the sewer being at one side, and an aperture to which a ventilating pipe may be attached in one of the other sides. Even if the last aperture be plugged up, and no ventilating pipe attached, any sewer air which can pass through the water from the third compartment into the middle one would escape by the grating into the open air, and could not get into the house, as the pipe from the house into the first compartment of the trap dips below the water.

In most cases, however, an ordinary siphon gully with a back or side inlet to receive the waste-pipe of the sink is all that is necessary, the waste-pipe itself being trapped immediately under the sink in the way described in the next chapter.

CHAPTER VI.

WATER-CLOSETS, SINKS, AND BATHS. ARRANGEMENT OF PIPES, TRAPS, &c.

Water-closets. The simplest form of water-closet is the common "long hopper" closet, consisting of a conical basin with a stoneware siphon trap below it. There is nothing to get out of order in these closets, but they are liable to get stopped up through an insufficient amount of water being used in them, and the basins often get very foul from the same cause, and from the fact that no water remains in the basin. They are very often supplied with water by means of a 4-inch service pipe, which cannot supply enough water to flush them properly. This pipe is frequently taken directly from a cistern supplying drinking water, or even, where the water service is constant, directly from the main water-pipes, provided with an ordinary stop-cock, or, perhaps, with a screw-down tap-a very mischievous plan, as the taps are frequently left turned on, and the water allowed to run to waste, sometimes emptying the cistern, and allowing foul air to get into it. When such pipes are taken direct from the main, the results are even more serious, as, if the water is, for any reason, turned off in the latter, foul air, and even liquid and solid filth, may be sucked up into the water mains and contaminate the water supplied next. To this cause a very

serious outbreak of typhoid fever in Croydon has been traced by Dr. Buchanan. The supply pipes for these closets should not be less than 1-inch in diameter, and should not be connected directly with the drinking water

Long hopper water-closet with supply-pipe direct from cistern.

cistern or with the main water-pipe, but with a waterwaste-preventing cistern holding about two gallons-(the quantity required to flush the closet) and supplied from the nearest water cistern, or in the case of constant supply, from the main water-pipe-the supply-pipe being guarded by a ball valve. The pipe from this waste-preventer to the closet is guarded by a valve, frequently the conical one known as the spindle valve, which can be al by means of a lever worked by a chain and ring.

action arrangement.

A. Valve on service pipe. B. Valve on communication pipe. C. Ball valve.

H

When the chain is pulled, the spindle valve is raised, and the two or three gallons contained in the water-waste-preventer are discharged into the hopper closet, while at the same time the ball valve is also raised by the lever, so that no water can come into the waste-preventer while the chain is being pulled. It will be seen that this and similar contrivances not only prevent direct connection between the water-closet and the drinking water of the cistern or main water-pipe, but also prevent an inordinate waste of water. An improvement on the ordinary hopper closet is the "Artisan" closet, made by Messrs. Dent and Hellyer, in which the hopper is provided with a flushing rim, which is far better than the old plan of shooting the water in at one side of the hopper. The basin of this closet is sometimes provided with a china tray to prevent slops being thrown over the rim. This arrangement is called "the Artisan Basin and Slop Sink combined" and is frequently very useful. In the "Vortex" closet, made by the same firm, the siphon is much deeper than in the "Artisan" closet, and the water stands in the basin. A two-inch supply-pipe is necessary, the water being discharged by a flushing rim, and also projected into the middle of the basin, as it is clear that a greater force of water is required to flush out so deep a siphon; three gallons of water are required. On the other side of the siphon is placed a ventilating pipe to carry away any foul air. The "Household" closet, made by Messrs. O. D. Ward and Co., is another form of short hopper closet, in which, however, the siphon without being deepened so