Busacca Gallery

Antique Nautical Maritime Measuring Parallel Chart Plotter And Navigation Tool Wood Boat Ruler: ANTIQUE PARALLEL RULE: This is a parallel ruler ship's chart map course tool nautical maritime antique. An antique parallel rule, made out of wood and brass, from the 19th century. Folded it is 6" long, extended it is 21" inches long. Quite beautiful and very rare. Antique Parallel Ruler, Nautical Maritime. Wood parallels, (oxidized) brass hinge partitions. Late 1800s. Marine grade brass bars, pivot points and lifting knobs. The rule is made in a fine grade, and has a old heavy duty used wax finish. Parallel rulers are used to plot direction on your nautical chart. They are, essentially, two straight-edges hinged so that they maintain the same angle. By alternating the moving edge, and securely holding down the non-moving edge, you can move the rulers about the chart while still maintaining the same angle. Signed CAPT Field's Improved. Captain William Andrew Field (c. 1796 - 1871)

Link: http://en.wikipedia.org/wiki/Parallel_rulers

Parallel rulers are a drafting instrument used by navigators to draw parallel lines on charts. The tool consists of two straight edges joined by two arms which allow them to move closer or further away while always remaining parallel to each other. The parallel ruler was invented in about 1584 by Fabrizio Mordente, but it was not in common use until the 18th century. Captain Field's Improved Parallel Rule In the 19th century, a Captain William Andrew Field (c. 1796 - 1871) improved the design by adding a protractor-style scale to the upper edge of one rule, and compass points to the opposing edge, which made reading bearings easier. Examples exist of boxwood, ivory or ebony, usually with brass hinges. The instrument usually had two links, but longer models sometimes had three, and sometimes the links were scissored. Another variation is the "roller" model which included a cylindrical roller for ease of use.