The marble top of a wash-basin should be an inch and a quarter thick, or, at least, an inch and an eighth. This admits of proper "dishing" around the basin, so that spattered water will run into the latter, instead of falling on the floor. With a slab seven-eighths of an inch thick, such as is sometimes seen, the dishing is too shallow to be of much use, and the slab is fragile.

The proper material for wash-basin slabs is what is known in the trade as "blue-veined Italian marble," being the product of the quarries of the Carrara region. This, although oil or ink will stain it slightly, is nearly non-absorbent; while the white or veined American marbles, sometimes substituted for it by designing contractors, soon become dingy, even colored soap being often sufficient to stain them.

Water-closets, especially of the siphon-jet type, are often defective, cracks occurring in burning which allow water to escape. Those made of vitreous china are much less liable than the cheaper earthenware ones to this trouble, and closets of the best class are alleged to be tested before they are sent out; but no tests beyond a hasty glance are applied to the cheaper ones. The dealer who sells the closet will generally replace a leaky one by a new one, but there is a plumber's bill to pay for labor in making the change, which he does not usually feel called upon to assume.

Marble slabs.

Water-closets.

Besides possible defects in the closet itself, the coupling connecting the supply-pipe to the flushing-rim often leaks, particularly when the closet has not been used for some time, and the leather washer of the coupling has become dry. The washer may, when the closet is used again, swell and become tight; but, if not, the coupling may be screwed up a little. In a similar way, the leather washer by which the connection between a short hopper and a lead trap under it is made tight often dries, so that, when the closet is used, water escapes upon the floor. The remedy for this trouble is to tighten the clamps by which the hopper and the trap are held together.

The overhead cistern of a water-closet often needs attention. If the ball-cock does not close properly, the water will overflow constantly into the bowl of the closet, and the ball-cock should be treated as described under the head of Supply-Pipes. It often happens, also, that a bit of lead, or mortar, or other obstruction, gets under the cistern-valve, preventing it from being dropped into place, so as to shut the water off; or it may be shaken out of place by a sudden jerk of the chain or rod, so that the water runs out of the bottom of the cistern into the bowl of the closet, the ball-cock of the cistern, meanwhile, pouring in a fresh supply. In this case, a moment's inspection of the cistern, or the simple pulling of the chain, followed by a slow and steady release, will often put matters right again, by enabling the cistern-valve to descend properly.

A few observations on the care of plumbing apparatus may close what is necessarily a long chapter. Naturally, the most dreaded enemy of all plumbing apparatus is frost, which will quickly destroy pipes and fixtures. Lead pipes suffer less from freezing than those of iron or brass, as they yield and bulge, opening only minute holes or cracks, instead of splitting. Pipes, both for hot and cold water, extending into rooms exposed to the cold, should have shut-offs, so that the water may be cut off, and the pipes drained, in cold nights; and pipes exposed to cold currents of air may with great advantage be protected by wrapping with hair felt, covered with stout cotton cloth, sewed on, as the felt without such protection is soon destroyed by moths. It should be remembered also that the space under the floors of an ordinary house is cold. Often, in winter, a thermometer let down through a hole in the floor into the space beneath will sink to a point thirty degrees or more below the temperature of the room, and where supply-pipes are run between the floor-beams they should always be protected. Such pipes must be laid on boards, firmly supported between the beams, and inclining a little, so that the water will drain out of them to whatever shut-offs may be provided. If this is not done, they will soon sag from expansion so that they cannot be drained, and will inevitably freeze and burst if left in cold weather. The wrapping of hair felt, or the more expensive magnesia covering, form the best protection for pipes in floors, but they are often buried in planing-mill chips, sawdust, or mineral wool, any of which will check the circulation of air around them, giving a certain protection.

The care of plumbing apparatus.

On very cold nights, it is sometimes advantageous to reflect that lead, iron, and brass, but particularly lead, are good conductors of heat, and that the warmth from a lamp, set at some accessible place under a pipe, may be conducted many feet along the pipe to some inaccessible and exposed place, which will thereby *be protected. For this reason careful architects sometimes arrange to have all the supply-pipes in a house pass at some point in their course through the kitchen, the heat from which is thus more or less disseminated throughout the system.

Another important circumstance is that hot-water pipes are usually the first to freeze. Of course, a pipe with an active circulation of hot water through it would not easily freeze, but there is rarely such a circulation in a house hotwater system, and the branches from the main system contain water which is usually cold; and this water, having had the air expelled from it by heating in the water-front of the range, has lost a powerful protection against freezing. Most plumbers believe that if a pail of boiling water, and one of cold water, are set out of doors on a cold day, the boiling water will freeze first; and, although this idea is not, perhaps, scientifically accurate, it expresses what plumbers find to be the relative effect of cold on hot and cold water pipes.