This is a Campbell-Stokes sunshine recorder, a meteorological instrument used to measure the duration of bright sunshine. [1, 2]
Function: It features a glass sphere that focuses sunlight onto a specially calibrated card, leaving a burn trace that indicates the duration of sun exposure.
Components: The device consists of the glass sphere mounted on a metal frame, often placed on a marble base for stability.
Usage: It is widely used by government meteorological services and has been a standard reference recorder since 1964