A Ball & Peg Oil Cap Lamp.
An oil cap lamp known as a “Ball and Peg which would be filled with oil and tied to your cap for light on the coalface.
Made from brass. Size 7″ x 2 1/2″ inches.
The ball was the reservoir that contained the oil and had a thick round wick, the peg was the handle that could be unscrewed from the ball, turned upside-down and screwed over the wick for transportation and safe keeping. Used throughout the 1800’s.
(This lamp has been heavily renovated and repaired).