A hollow hemisphere known as a scaphe dial (from the Greek for 'boat').
The shadow of a notch on the edge of the hemisphere indicates hours between noon and 6pm on this west-facing vertical dial which is incorporated in a memorial.

Spherical dial made for the interactive science centre at Green's Mill, Nottingham home of George Green, mathematician.
Time is told by swinging the stainless steel 'arm' round until it is pointing directly at the sun and its shadow is narrowest. Time is then read off the hour band on the stone sphere.