The Level
In the southern celestial hemisphere, between Virgo to the west and Scorpius to the east, there sits a constellation the Babylonians called the Claws of the Scorpion. To the Romans it was Libra (a word meaning balance) and symbolized law, fairness, and civility. It is from this latin root that we get caliber, deliberate, and a bit less predictably, level (from the intermediary, libella).
Astrological map of Libra by John Bevis, 1750, gifted to John Conybeare, Dean of Christ Church, Oxford
A level is any device used for establishing a horizontal line or plane. The Egyptians bored holes through boards and filled them with water to level their Great Pyramids as far back as 1100 BC. A later iteration called a chorobates was popularized by Vitruvius, but was too large and unwieldy to be widely practical. The modern version seen here is the spirit or bubble level and was invented in 1661 by the French born Melchisédech Thevenot, Royal Librarian for King Louis XIV.
Portrait of Melchised Thevenot renedered sometime in the 17th century by an unknown author.
The alcohol (spirit) used by Thevenot provided several advantages over water, including lower viscosity and surface tension for quicker and more precise readings, as well as much broader temperature stability in liquid form, preventing it from freezing and bursting the tube. The lengthier the level, the more cumbersome it is to use. The shorter the level, the less accurate it is over long distances.
For inherently straight materials, such as metal corner posts, this blue 9” torpedo level is handy and quick. Wood, however, has curves, twists, and other in- trinsic inconsistencies that benefit from something longer. When laying up plank siding, Ron cut a level sized hole in one plank, added a handy ledge, and crafted at once the perfect combination spacer and leveling jig.
Knowledge Sources
The History of Technology, editedbyCharles J. Singer, 1954 to 1978. Clarendon Press [Oxford Univ. Press] https://en.wikipedia.org/wiki/Chorobates
https://www.merriam-webster.com/dictionary/level
https://hausoftools.com/blogs/news/history-of-levels-spirit-levels-and-measuring-levels
