ment 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. The cases in

which it is more advisable to use this trap than ordinary siphon gulleys, will be mentioned in the next lecture.

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

Water-closets. The simplest form of water-closet is the common 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 2-inch service pipe, which cannot supply water enough 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 soaked 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 cistern or with the main water-pipe, but with a water-waste preventing cistern holding two or three gallons—the quantity required to flush the closet. I have here several specimens of such cisterns, lent by Messrs. Hayward, Tyler & Co., and by Messrs. Tylor & Sons. They are supplied from the nearest water cistern, or, in the case of a 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 raised by means of a lever worked by a chain and ring. 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. Other water-waste preventers will be mentioned shortly. An improvement on the ordinary hopper closet is the "Artisan" closet, made by Messrs. Beard, Dent, & 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. In the "Vortex" closet, made by the same firm, the siphon is much. deeper than in the "Artizan" closet, and the water stands in the basin. A twoinch 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 On the other side of the siphon is placed a ventilating pipe to carry away any foul air.

We now come to various forms of "Wash-out" closets, the first being Jennings' "Monkey" closet. In this, a small amount of water remains in the basin, the opening out of which into the siphon is not at the bottom, as in the case of the hopper closet, but on one side. The advantage of this form of closet is, that it is not possible, as is the case with hopper closets, for careless persons to go on using the closet without flushing it with water, as the soil remains in the basin until it is flushed out. Hopper closets, on the other hand, may be used for a long while without any supply of water at all, and this is the way in which pipes frequently get stopped up. In the monkey closet the basin and siphon are all in one piece of earthenware. In Woodward's "Wash