Lens
Category
Machinery and industrial devices
Date
circa 1873
Materials
glass and bronze
Measurements
2612 x 2438 x 2383 mm
Place of origin
Smethwick
Collection
Cwrt, Henfaes and Porth Simdde, Gwynedd
NT 1703101
Summary
Lighthouse optic. A First Order five panel catadioptric, built by the Chance Brothers of Smethwick, c1873. Constructed in bronze and glass, with five seperate panels to give it its unique flash character of 5 flashes every 15 seconds. The optic floated on bath of mercury and was rotated with two electric motors (one acting as standby should the other break down) at a constant rate of 4 revolutions per minute.
Provenance
The optic was first installed at Bardsey Island lighthouse in 1873. The light comprised of an oil light and dioptric lens until 1973, when an electric filament lamp was installed. The optic was made by the Chance Brothers of Smethwick, the world-class lighthouse optic manufacturer that supplied many or most of the Trinity House's optics. This optic is on loan to the National Trust from The Corporation of Trinity House for a period of 10 years.