of standard iron-pipe gauge. Connections on brass pipe and between brass pipe and traps of iron pipe must not be made with slip joints or couplings. Threaded connections on brass pipe should be tapered and of the same size as iron-pipe threads. The following average thicknesses and weights per lineal foot should be employed:

WEIGHT OF BRASS SOIL, WASTE, AND VENT PIPE.

Brass ferrules should be bell-shaped, extra-heavy cast brass, not less than 4 in. long and 24 in. in diameter. The least weight of cast-brass ferrules and solder nipples should be as follows:

WEIGHT OF BRASS FERRULES AND NIPPLES.

Particular care should be taken to inspect all cast-brass ferrules before calking them in place, as they are very liable to have sand holes in them, which will cause annoyance in testing the roughing when finished.

Recess Drainage Fittings.-These fittings, sometimes called flush fittings, are used in connection with wrought-iron pipe in the installation of drainage systems. The Durham system is constructed of wrought-iron pipes and flush fittings. The essential feature of these fittings is that the bore of the fitting is the same as that of the pipes with which they are used. The fittings can be had plain, dipped in asphaltum, or galvanized, the latter being commonly used in conjunction with galvanized pipes If ordinary pipe fittings are used for drainage purposes, the pipes will soon become choked, because the ends catch and hold solid matter.

A number of the fittings commonly used by plumbers are shown in Fig. 3. Commencing at the top and reading to the right their names are: Y branch; TY branch; 90° long bend; 45° bend; double T Y branch; TY with side outlet; short 90° bend; 2210 bend; T branch; 60° bend; 1140 bend; running trap with two clean-outs; one half S trap with vent outlet.

Lead Pipes.-The weight of lead pipe should conform to the following table:

WEIGHT OF LEAD SOIL, WASTE, AND VENT PIPE.

This grade is known in commerce as D. All lead traps and bends should be of the same weight and thickness as their corresponding pipe branches.

Miscellaneous Materials.-Oakum is a hemp fiber moistened with pine tar, and capable of being packed very tightly into crevices. It is used extensively for calking joints in soil pipe.

FIG. 3.

Asphaltum is a native mineral pitch or bitumen used extensively for coating pipes. It is black or dark brown in color, and fractured surfaces have a high luster. The specific

gravity is about 1.10. It melts readily and burns without residue, being completely soluble in petroleum or turpentine. Pipes that are to be coated should be heated to the melting point of the asphaltum before being dipped.

Plaster of Paris is used in plumbing chiefly for setting marble work. It should be mixed with water in small quantities to the consistency of thick cream and should be used as quickly as possible, for it sets rapidly. It should never be disturbed when setting nor used after it has begun to set.

Portland cement is used by plumbers chiefly for joining earthenware pipes. For that purpose it is best when mixed with an equal quantity of clean, sharp sand. Good Portland cement will set under water.

Rosendale cement is not suitable for joining earthenware pipes, but may be used for building manholes and similar masonry. It is similar to Portland cement, but does not possess the same degree of strength or the property of setting under water.

Glaziers' putty is a mixture of about 7 parts, by weight, of whiting to 3 parts of boiled linseed oil. When mixed with white or red lead it makes a suitable cement for bedding down water closets.

Red lead is an oxide of lead and is sold in powdered form. It is used in plumbing chiefly as a paste for pipe threads, and to mix with putty for bedding purposes. Red lead is prepared for use by being mixed to the consistency of batter with boiled linseed oil; only a small quantity should be mixed at a time, as it sets in a short time and becomes very hard.

White lead is a carbonate of lead ground to a fine paste in boiled linseed oil. It is the basis of nearly all good house paints, and is used by plumbers for the same purpose as red lead.

INSPECTION OF MATERIALS.

To install a creditable plumbing job it is necessary to use good material only. All materials should be inspected when received and before being accepted.

Black sheet iron should be examined for flaws or holes on its surface, for equality of thickness, and as to its liability to crack if bent sharply either with or across the grain.

Galvanized sheet iron should be examined for the same defects as black sheet iron. The zinc coating may be tested by bending the iron at a temperature of about 60° or 70° F. If the zinc adheres properly to the iron it will not scale or peel off.

Sheet copper, sheet lead, and sheet zinc are generally accepted as they are placed on the market.

Lead pipe should be soft and pliable. Examine for kinks, bruises, and punctures caused by rough handling during shipment; otherwise, it is placed on the market in good condition and requires no further inspection.

Tin-lined lead pipe should have its interior surface examined, if possible, to see if it really is tin-lined. Shave off the end of the pipe square and clean, and ascertain the thickness of the tin lining by breathing on the freshly cut end. The breath will discolor the surface of the lead with a thin blue coating, and the tin will remain bright. The thickness of the tin lining will thus become visible.

Block-tin pipe, like lead pipe, is generally accepted as reliable in the form placed on the market. Pure block tin may be detected by a peculiar crackling noise it makes when being bent at ordinary temperatures.

Seamless brass tubing should have an equal thickness all around, and should be slightly annealed to prevent its being too brittle for working. The very hard varieties are liable to split, not only while in the pipe vise, but after they have been in service for some time. Tinned semiannealed pipe is strictly reliable.

In brazed brass and copper tubing the brazed seams should be examined carefully. The seams should be uniformly loaded with hard solder and thoroughly sweated.

Galvanized-iron pipe is sometimes partly choked by the zinc used to galvanize it clogging in lumps. This may be detected by rolling a marble a size smaller than the pipe through its entire length, or, if possible, by looking through it.