Description from Garden Objects
The light mill is a simple, but mesmerising instrument constructed from an airtight glass bulb containing a partial vacuum. Inside the bulb is a set of four vanes, each of which reacts to light, causing them to rotate on their axis, the more intense the light the faster they spin. A perfect curiosity for the contemplative gardener.
The light mill was originally developed by Victorian scientist Sir William Crookes during his investigations into electromagnetic radiation intensity.
Dimensions: globe 8cm.