You’ve likely found vials from a vintage or antique spirit level—also known as a "bullseye level" or machinist’s level.
🔍 What It Is:
Those small glass tubes containing three tiny ball bearings are not random curiosities—they’re precision components from an old spherical (bullseye) spirit level, commonly used in:
- Carpentry
- Masonry
- Machinery alignment
- Surveying equipment
Unlike standard linear spirit levels (with one curved tube and a single air bubble), bullseye levels use a circular, dome-shaped glass capsule filled with liquid and often multiple small steel balls or a single bubble to indicate levelness in two dimensions at once.
However, in some older or specialized designs—especially European or industrial models—the "bubble" is replaced or accompanied by tiny steel ball bearings that roll to the lowest point, helping the user visually confirm true level from multiple angles.
🧪 Why Ball Bearings Instead of a Bubble?
