In Spanish: de Cadenas a Leguas marinas
Chains
Unit of length equal to 66 feet, used especially in the U.S. public land surveys. The original measuring instrument (Gunter's chain) was literally a chain consisting of 100 iron links, each 7.92 inches long. Steel-ribbon tapes began to supersede chains around 1900, but surveying tapes are often still called "chains" and measuring with a tape is often called "chaining". The chain is a convenient unit in cadastral surveys because 10 square chains equal 1 acre.
Nautical Leagues
A nautical league was 6,080 yards - or three nautical miles (each league being 6,080 feet).
Note that there also US Leagues, UK Leagues and UK Nautical Leagues which all differ.
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