PLUMB. Carpenters, shipwrights, masons, and other craftsmen who are obliged to align their works along the plumb-line, that is to say, perpendicular to the horizon, have various kinds of instruments they call plumb , because of a small piece of this metal that forms a part of it, [1] although one most often keeps a piece of copper or iron there.

The plumb of Masons and Joiners is usually copper, in the form of a small cylinder, of six or seven lignes in diameter, [2] and an inch in height. It hangs from a string, which is called the cord [ la corde ou cordeau ], which passes through a small plate, also of copper, square and very thin, called the cat . This plate, which is only as wide as the cylinder, can be made to go up and down at will along the cord, and is used to press against the work that one wants to make plumb .

The Carpenters’ plumb has no cat, is flat in the shape of a day rose, about two inches in diameter: it is made of lead , iron, or copper. It is pierced so that one can see through it, and the worker can better look at the place where he wants to prick the wood, that is to say, to mark it.

The level plumb , which is a real level, and a plumb whose cord descends along a ruler of wood or copper, laid out perpendicular to another.

The bank plumb is nothing but a plain level whose cord can be moved.

The ruler plumb is a simple ruler that has a notch at its base, and a perpendicular line drawn from top to bottom, which holds the cord where the plumb is attached.

1. In French, the first meaning of plomb is lead . The connection between lead ( plomb ) and plumb ( plomb ) is lost in translation.

2. A ligne is a historic unit of measurement used in France before the 19 ^th century. Its conversion to the modern meter: 1 ligne = 1/443.296 m.