General Information

Serial #

52

Part Number

14

Total Parts

16

AKA

N/A

Patents

N/A

General Description

metal, including brass/ selenium cell/ paper

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

19.2 cm

Width

19.0 cm

Height

6.0 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Communications

Category

Telegraphy

Sub-Category

N/A

Manufacturer

AKA

SULLIVAN

Country

England

State/Province

Unknown

City

London

Context

Country

Unknown

State/Province

Unknown

Period

Unknown

Canada

Unknown

Function

Selenium is a substance with marked photosensitive properties and a resistance that varies inversely with illumination. In general, a selenium cell is an arrangement in which is mounted a thin film of selenium, with electric terminals, for utilizing the photoconductive property of selenium. A selenium cell magnifier is an instrument used in telegraphy for the magnification and increase of submarine cable signals.

Technical

The selenium cell magnifier was a device for improving submarine telegraph signals. Selenium is a substance with marked photosensitive properties and a resistance that varies inversely with illumination. In a selenium magnifier, a beam of light is reflected onto a number of selenium resistance units or cells from a mirror, the movement of which is controlled by the coil of a telegraph signal receiving instrument The cell forms part of a bridge arrangement connected to a recorder (Ref. 4). In 1914, K.C. Cox applied for two patents for his selenium cells for use in telegraphy. The arrangement was for a collimated beam of light to be split by a slit screen into a series of bars, reflected off a mirror galvanometer onto a selenium cell. This cell was a series of long, very thin strip elements of selenium, separated by brass foils. The light bars matched the spacing of the selenium elements, each straddling a pair of elements, whose resistances thus change differentially as the light is deflected. A multiplicity of light bars and selenium elements multiplied the effect; connection, through the brass foils, into a Wheatstone bridge, was used for actuating the succeeding, moving coil relay stages. The cell was constructed by stacking and clamping mica sheets with interleaving brass foils. The foils, being slightly wider than the mica, left a series of shallow spaces into which heated selenium was melted. Once solid, the surface was polished and annealed to form a photosensitive surface. (Ref. 1).

Area Notes

Unknown

Details

Markings

incised lettering on brass reads ‘SELENIUM CELL', ‘K.C. COX'S PATENT', ‘No. 52' and ‘H.W. SULLIVAN LTD./ LONDON'/ incised white 'A', 'C', 'B', 'D', 'E' and 'F' for contacts

Missing

N/A

Finish

dark gold coloured metal with black painted parts

Decoration

N/A