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Description: | SMT.2 (scribed on the glass envelope). SMT.2 (written in black ink on the end cap). A (moulded or stamped onto the top of the cane supporting the element) MANU [General Electric Company of England] circa 1925 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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