After all the traps which have screws or caps have been opened, sponged out, and the caps replaced, the water-closet traps, which have no trap-screw, must be cleared of water by means of a sponge tied to a stick or wire. With most closets, it is easy to see when all the water has been removed, the trap being directly under the basin; but in closets of the "washout," or "Brighton" class the trap is concealed. Some patterns of washout closets have a removable cover over the trap, by means of which the trap is easily reached and cleared of water; but, where no such cover is provided, the trap may still be reached with a sponge attached to a bent wire, pushed down through the outlet by which the water escapes from the basin, and trial will show when all the water is removed. In closets of a still older type, like the "Jennings," or the "Demarest," with side outlets, the trap, if any exists, may be reached by unscrewing the plate through which the handle works, and lifting out the plug.

With closets of the siphon-jet pattern a little water remains, after the trap has been cleared, in the jet-tube. There is not usually more than half a teacupful; but, as this is quite enough to destroy the closet, if it should freeze, it must be removed, either by opening a little screw inserted by some makers in the outside of the closet, near the bottom, or by means of a small sponge, tied on a wire, inserted through the jet opening. This operation, although rather tedious, is easier and safer for amateurs than the complete removal and inversion of the closet practised by plumbers.

If there is a main trap at the foot of the soil-pipe, the brass screw in the hand-hole must be removed, and the trap dipped or sponged out in the same way; and the plumbing system of the house may then be considered safe against freezing. After the sealing water of the traps has, however, been removed in the way described, there is no longer anything to prevent air from the sewer from entering the rooms through the unguarded outlets of the fixtures; so that it is necessary to stop these with wads of paper, and to paste pieces of thick paper over the overflow openings, or the carpets and furniture of the house, when it is occupied again, may be found offensively, and even dangerously, saturated with the foul emanations of the drains.

Many plumbers, who have observed that traps, after thorough clearing out, often collect water in cold weather, probably from the condensation in them of the warm and moist vapors of the sewers, put a handful of coarse salt in the main trap, after clearing it out, and before replacing the trap-screw; and the same treatment is sometimes applied to water-closet traps, and to the jet-tubes of siphon-jet closets. The action of the salt is, if water should collect by condensation in the trap, to dissolve in it, forming a strong brine, which, if it freezes at all, only congeals into a soft mass, which is harmless. For iron main traps, and for closets of vitreous china, this treatment is often useful; but salt should not be put into a brass or plated trap, nor should it be allowed to come in contact with brass trap-screws or other fittings, on account of the danger of corrosion; nor should it be put into a closet basin of ordinary earthenware, the glaze of which may be affected by it.

Salt.

Where plumbing work is left in warm weather, the process of protection is much simpler. It is not necessary to drain the supply-pipes, but it is advisable to shut off the water at the cellar wall, or even at the street, as a precaution against waste of water through the dripping of a faucet, or possible leaks through the spontaneous splitting of a brass pipe, or the breaking of a soldered joint, or from lightning, or from the gnawing of a lead pipe by thirsty rats. In an empty house any of these occurrences may cause great damage. In regard to the traps there is, of course, no danger to be anticipated from freezing, but the circulation of air which goes on in most modern drain-pipe systems causes the evaporation of the water in the traps; so that, after a period varying from two to four weeks, these lose their seal, and sewerair passes freely through them, and escapes into the rooms. It is, therefore, desirable that a house left vacant during the summer should be visited about twice a month, and water poured into the various fixtures, so as to keep the traps replenished; but, where this is impracticable, oil should, before the house is closed, be poured into each fixture. Olive oil, or lard oil, or any lubricating oil may be used, or even crude petroleum, but not kerosene, which is too volatile for the purpose. A very small quantity in each trap is sufficient, the object of using it being to cover the water in the trap with a floating film of oil, which will keep it from evaporation for a long time. Glycerine is often used for the same purpose, and answers very well, although more of it is needed, as it dissolves to some extent in the water.