Historical information

The tool is used for establishing a horizontal plane, it consists of a small glass tube containing alcohol or similar liquid and an air bubble. The tube is sealed and fixed horizontally in a wooden or metallic block or frame with a smooth lower surface. The glass tube is slightly bowed, and adjustment to the horizontal is indicated by the movement of the bubble. The device is on a level surface when the bubble is in the middle of the glass tube. The level sensitivity is proportional to the radius of the curvature of the glass.
The spirit or bubble level consists of a sealed glass tube containing alcohol and an air bubble. It was invented in 1661 and was first used on telescopes and later on surveying instruments, but it did not become a carpenter's tool until the factory-made models were introduced in the mid-19th century. The circular level, in which a bubble floated under a circular glass to indicate the level in all directions, was invented in 1777. But It lacked the sensitivity of the conventional level.

Significance

A hand tool that has not changed much since its invention in 1661, this tool is used today and although the materials it is made from have changed it's use has not.

Physical description

Spirit level wooden with two windows one of which has a piece of brass sheet metal protecting it.

Inscriptions & markings

None