The spirit level, or bubble level, is a tool used for checking if a surface or item is horizontal (level) or vertical (plumb). It was first invented in the 1660’s by  Melchisedech Thevenot (born in either 1620 or 1621; died 1692). According to Wikipedia, “Thevenot was an amateur scientist and patron of many scientists and mathematicians. He was wealthy and well-connected, later becoming the Royal Librarian to King Louis XIV of France. Thevenot invented the instrument some time before February 2, 1661.”

spirit level

Image credit: David Jones

The first levels were quite complicated to use. The level that you have in your toolbox was created in 1920’s by Henry Ziemann, the founder of Empire Level Mfg. Corp., who developed the single vial filled with a colored spirit or liquid. The glass vial is actually slightly curved and has two indicator lines. When the trapped air bubble is within the lines, your surface is level or plumb. Alcohol is the liquid of choice for a spirit level. The low viscosity and surface tension means that the air bubble travels faster. Additionally, alcohol isn’t susceptible to cold or freezing temperatures. A colorant (usually yellow or green) is added to help make the bubble more visible.

The level is quite a versatile tool to have on hand. In fact, you may end up having several in your toolbox. Longer ones are perfect for aligning longer surfaces or marking level spaces on a wall, for example. Shorter ones are perfect for one-handed uses like trying to hang a shelf or picture. There are even levels with magnetic sides that you can fix to metal, making two-handed tasks a bit easier. Levels can be purchased in plastic, metal or wood. Vintage levels are also a unique addition to your toolbox.