Note 234 — Chapter XII · Opening of the Liverpool and Manchester Railway, and Extension of the Railway System.
Reading edition
Tubbing is now adopted in many cases as a substitute for brick-walling. The tubbing consists of short portions of cast-iron cylinder fixed in segments. Each weighs about 4½ cwt., is about 3 or 4 feet long, and about ⅜ of an inch thick. These pieces are fitted closely together, length under length, and form an impermeable wall along the side of the pit.