The material of which the house-drain, soil-line, and waste-line are made is usually cast-iron, and of a grade known as extra heavy. The joints are the bell-and-spigot type, which are stuffed with oakum and then closed tight with 12 ounces of fine, soft pig lead for each inch in diameter of the pipe. Branches are usually of galvanized wrought iron or lead, but lead should be limited in use in modern plumbing, although the term plumbing originated from the Latin word for lead. The common limitations upon the length of branches of lead pipe are: 8 feet for 1½-inch pipe, 5 feet for 2-inch pipe, 2 feet for 3-inch pipe, 2 feet for 4-inch pipe. The parts of the branch pipes which are visible are generally made of brass nickel-plated. The joints between lead pipe and lead pipe, and between lead pipe and brass pipe, are made by the common wiped joint. Joints between lead pipe and cast-iron pipe are made by first wiping the lead pipe to a brass ferrule, a piece of pipe in shape like a bell with the top cut off, and then inserting and caulking this into the cast-iron pipe. The joints between wrought-iron pipes are made with the screw joint, and between wrought-iron and cast iron with the screw joint, by using connections of malleable cast-iron which have been threaded. The usual sizes for branch wastes from the fixtures are as follows: for water-closets 4 inches, for bathroom-tubs 1½ inches, for lavatories 1½ inches, for kitchen-sinks 2 inches, for laundry-tubs 1½ inches, and when in sets of three 2 inches. The size of the waste from the bathroom-tub can be increased to 2 inches with great advantage, if the additional slight expense is not objectionable. The vertical soil-lines should be supported at each floor by metal straps placed under the hub and fastened to the floor-joists. It is very important to properly flash the base of the projecting portion of the soil-line above the roof. Wherever the branch soil-line to the water-closet is connected, a short TY connection may be employed in order to avoid the projection of the parts of the pipe beyond the plane of the ceiling in the floor below. However, no short TY connections should be made in any horizontal pipes.