A Colliery Lamproom Photometer.
Manufactured by Oldham & Son Ltd, Lamps.
Made from wood, metal and leather. Size 15″ x 10″ x 10″ inches.
These photometers were used to measure the brightness of the miners cap lamps. The inside of the photometer is painted white with an internal diffuser and a light gauge. The activated cap lamp is placed against the circular frosted glass aperture at the back of the photometer, the light it produces is shown in candle power on the external light gauge situated on the top of the photometer.