The water-test is applied by plugging the pipe carefully, and closing all openings below a certain point, and then filling it with water to that level. If there is any leakage, the water-level will gradually sink. If the pipes are tight, it will remain the same.
Peppermint-test. (See hereafter.)
26. Oakum is packed into the space between the spigot-end of one pipe and the hub of the other, and driven against the bead above mentioned. This packing is called a gasket. Melted lead is poured in on top of the oakum, and, when it has cooled, is driven in tight with a calking iron and mallet. When ordinary pipe is used, the calking will sometimes split the hub, and this furnishes an argument for the general use of extra-heavy pipe.
Iron-filings, etc., making what is called a rust-joint.
27. Ferrules, or sleeves, are used because lead pipes are too soft and yielding to withstand the calking. Lead can not be soldered to iron, and therefore brass or copper has to be used. If iron ferrules are used, the lead pipe must be turned up on the outside far enough so that its edge shall be covered by the melted lead used in calking, so as to prevent leakage of gas, as hereafter described. (See “Bad Odors,” 1, b.)
28. Wiped-joints are those always used for lead pipe, and are indicated by a raised ring of solder surrounding the pipe.
29. A trap, with a good water-seal, is an effective barrier against the passage of sewer-air or particles of organic matter. The experiments of Carmichael, confirmed by Wernich and Pumpelly, have amply demonstrated that sewer-air passes through the water-seal in such minute quantities that it can not possibly harm any one, and that solid particles of matter can not pass at all.
Separate traps, except, etc. (See “Bad Odors,” 1, d.)
33. Siphonage. (See “Bad Odors,” 1, d 37.)
37. Overflow-pipes from fixtures. It is better to connect them with the trap below the water-level. (See “Bad Odors,” 1, d.)