19th Century Brass Astrological Volvelle, believed to be Persian. A volvelle or wheel chart is a type of slide chart. Ours is a brass construction with rotating parts. It is considered to be an early example of an analog computer. Early examples are found in the pages of astronomy books and our brass version is considered to be Persian. Abu Rayhan Biruni (c.1000) is a Persian astronomer who made important contributions to the development of the volvelle.


**Diameter**
34 inches


**Depth**
4 inches