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Description: | PATENT GEC LTD 26 OSRAM 200 V 60W 21 MADE IN ENGLAND (acid etched on the glass envelope) MT4 (scribed on the glass envelope). A (moulded or stamped onto the top of the cane supporting the element) MANU General Electric Company Limited of England. circa 1925 Osram Works, Hammersmith, London, England. DES after SWAN,Joseph,Wilson,Sir. 1878 Newcastle-Upon-Tyne England This is a 200 volt 60 Watt general lighting service lamp with a Swan double contact bayonet two pin cap type No B22/25x26 and a clear bell shaped envelope. The single ductile tungsten squirrel cage filament is electrically welded to the copper sheathed nickel iron lead in wires. It is supported by a lower set of eight molybdenum wires and an upper set of nine mounted on a central glass cane. The support wires are in the form of fine crooks not loops.The first tungsten filaments were developed circa 1906 using a process similar to the squirted carbon filament but a ductile tungsten process, by which tungsten powder is compressed and then forged into billet before being drawn through a series of diamond dies, was developed in 1909. The envelope is a machine made vacuum type without a pintel or pip. The bulb being evacuated via a hole blown in the base of the cane. | 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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