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Description: | ROYAL "EDISWAN" POINTOLITE 25 MADE IN ENGLAND 100 C.P. 100V-250V (black stencil on the end cap) MANU The Edison Swan Electric Company Limited. circa 1952 Head Office, 155, Charing Cross Road, London, W.C.2.
Works, Ponders End, Middlesex. England DES after MULLARD, Stanley Robert, 1914 Duck Lees Lane, Ponders End, Enfield, Middlesex, England. This is a non fixed focus Pointolite lamp primarily used in microscopy and photography where a steady light source was required. A 100 C.P. of this type of AC Pointolite lamp produced about 1,330 candles/square inch max. The lamp worked by striking an arc between a tungsten spiral or ioniser and a tungsten bead. This version is designed for Direct Current operation. The tungsten spiral is partially inside a tungsten/thorium oxide tube and as the lamp reaches its operating temperature the arc transfers from the tungsten to this tube. In this example this is achieved by mounting the tungsten bead on a bimetallic strip. The lamp is filled with a nitrogen argon mix and fitted with a standard Swan triple contact bayonet cap. The tungsten arc incandescent lamp was described by A.E. Gimingham and S.R. Mullard, Journ., I.E.E., 1st December 1915. N.B. Gimingham was Crookes' assitant and inventor of the Gimingham pump used by Ediswan at Ponders End to pump down Ambrose Fleming's vacuum tubes for his rpatent work on the thermionic valve. | License: | http://www.hmag.gla.ac.uk/spirit/rights/ | Publisher: | Hunterian Museum and Art Gallery, University of Glasgow | Rights holder: | Hunterian Museum and Art Gallery, University of Glasgow | Subjects: | SCIENTIFIC COLLECTION : | Source: | Hunterian Museum | Creator: | Hunterian Museum and Art Gallery, University of Glasgow | Identifier: | http://www.huntsearch.gla.ac.uk/cgi-bin/... | Language: | en-GB | Go to resource |
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