=Valveless or Hopper Closets=, of which the =Wash-out, Wash-down and Syphonic Closets=, are the chief forms, present certain advantages over the valve closet. There is less apparatus to get out of order and no metal to become foul. They do not require an overflow pipe, as water can escape freely through the trap of the closet. Valveless closets need not be encased by wood-work, thus ensuring freedom from spillings of foul water, and they are more easily used than valve closets for the discharge of bedroom slops, thus obviating the necessity for a special housemaid’s sink. Valveless or hopper closets are cheaper and simpler in use than valve closets, and when in use are equally sanitary. If a house is left empty for a considerable time, the water in the trap may, however, become evaporated, an event much less likely to occur with a valve-closet. The latter are furthermore less noisy when flushed. With a valve to hold up the water in the pan, as in the valve-closet, a much larger quantity of water can be retained than with a hopper closet. Hence the importance of the latter having such a shape as shall prevent fouling of the basin by fæces. One of the older hopper closets was the =long hopper= shewn in Fig. 25. In this form the pan is conical in shape, its sides necessarily becoming fouled by its use, and the spiral flush, the point of entry of which is shewn in the figure is quite insufficient for cleansing the pan. Of =Short hoppers= the best has a nearly vertical back as shewn in Fig. 24, a rim-flush, by means of which at least two gallons of water are discharged with the fæces, and the pan is thoroughly cleansed. [Illustration: FIG. 24. RIM FLUSHING WASH-DOWN BASIN.] The =wash-out closet= is shewn in Fig. 26. In it a certain amount of water is kept in the upper part of the pan by a ridge over which the fæces have to be driven before entering the trap. The force of the flush is thus broken. In this closet a large area is liable to be fouled, and it is now almost entirely disused. [Illustration: FIG. 25. SHORT HOPPER CLOSET. LONG HOPPER CLOSET WITH SPIRAL FLUSH.]