When all the iron piping in the house is completed, the tightness of the joints should be thoroughly tested, before connecting the fixtures. The test which is mostly used, is the "water pressure test." The end of the iron pipe outside of the foundation walls is tightly closed by a wooden plug, or better, a disc of india rubber, which can be squeezed between two iron discs. All branches of soil pipes and waste pipes are similarly closed. The pipes are then filled with water, which must stand in them for some time. If the subsequent inspection shows a lowering of the water level, there must be a leak at some joint, or else some" defect exists in the iron piping. Of course the leak must be found and repaired, and the test should then be repeated, until all joints are water and air tight.

An equally reliable pressure test is made by using a force pump and a ma nometer.

For occasional inspections of old plumbing work, and in making sanitary examinations of houses the "peppermint" and the "smoke test" become useful. The peppermint test is thus described: "When called on to detect a leak in the soil pipe of a house, the plumber goes at once to the roof, if the soil pipe be carried above the roof; if not, he goes to the uppermost water closet, and poors into one or the other something like an ounce of peppermint, and follows it up with enough water to insure its being carried the full length of the soil pipe. (The top of soil pipe should be closed, in or der to prevent the oil from escaping into the outside air.) "Another man then traces the soil pipe from the bottom, throughout its course; knowing that if there is any crevice through which sewer gas can enter, the pungent odor of the volatile essential oil will be readily perceptible even in the presence of odors of a baser kind. Great care must be taken not to carry the peppermint about the house, otherwise the smell cannot be traced to the drains."

Captain Douglas Galton describes another test thus: " To test the drains the fumes of ether or of sulphur may be used. If ether is poured down a soil pipe the fumes will be perceptible in the house at any leaks in the soil pipe or failures in the traps. Sulphur fumes may be applied by putting into an opening made in the lowest part of the drain an iron pan containing a few live coals, and throwing one or more handfuls of sulphur upon the coals, and closing up the opening to the drain with clay or otherwise. The fumes will soon be very perceptible at any leaks or rat holes in the soil pipe, drains or traps."

The connections between fixtures and the soil or waste pipes are made with lead pipe, which can easily be handled, and may be bent and cut to suit all possible positions, and requires but few joints. It is manufactured in long coils, of all sizes and of any desired thickness. In good plumbing work only heavy lead pipe should be used to prevent its being quickly destroyed by the corrosive action of sewer gas. It is desirable that lead pipe should be used as little as possible in concealed places, as it may be gnawed by rats or split by nails through carelessness of carpenters.

It is not uncommon to find vertical waste pipes of lead, as these are easily placed inside of a partition and covered with plaster. But this cannot be regarded as good practice; iron for waste pipes is decidedly to be preferred.

Vertical lines of lead pipe should be fastened to boards by soldering hard metal tacks to the pipe and screwing the flanges of the tacks to the board. Horizontal lines should be continuously supported on boards between joists.

Lead pipes are mostly joined by what is called a "wiped joint." The end of one pipe is flanged out so as to form a cup, into which the other pipe, the end of which should previously be sharpened, is introduced. Hot solder is then applied to the joint, and wiped around it so as to form an oval lump.

Where lead pipes are joined to iron pipe, the connection should be effected by means of a brass ferrule of the same bore as the lead pipe, and soldered to it, wherever space allows, by a wiped joint. The ferrule is introduced into the hub of the iron pipe, and caulked tightly with a gasket of oakum and molten lead.

The size of lead waste pipes should be as small as is consistent with the office which they have to perform. Wastes for bath tubs or laundry trays should be sufficiently large to empty these vessels in a short time.

The following sizes of waste pipes for fixtures should be recommended:

Local conditions will, in some cases, demand a deviation from these sizes.