Biform lens

Chance and Co.
National Trust Inventory Number 238453

Category Technological items
Date 1915
Materials Glass, iron and mercury
Measurements
Place of origin Smethwick
Collection Souter & the Leas, Tyne & Wear (Accredited Museum)
Not on show

Summary description

Biform optic or lens with a wide base turntable of metal, the catadioptric lens has three faces consisting of 1008 pieces of glass set in a metal frame. This is supported on an iron base with twelve guide wheels which keep the lens in place as it effortlessly rotates on a flotation tank of mercury, when in use the light turned at four revolutions per minute. Originally Souter was a white light, but in September 1919 it was changed to red, the filter is visible through gaps in the lens.

Makers and roles

Chance and Co., photographer

Related items

Place of origin Smethwick (7)
Materials Glass (57465)
Metal (157702)
Category Technological items (2968)
Collection Souter & the Leas, Tyne & Wear (Accredited Museum) (1687)
Periods 20th century (150506)
Maker Chance and Co. (5)
Subjects
Object Type Biform lens (1)

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