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Description: | ROBERTSON 250-18-C1 (acid etched on the glass envelope). MANU Robertson between 1910 and 1922 [England] DES after SWAN,Joseph,Wilson,Sir. 1878 Newcastle-Upon-Tyne England DES after EDISON,Thomas,Alva. 1879 Menlo Park, New Jersey United States of America This is a 250 volt 18 candle power general lighting service lamp with a Swan double contact bayonet two pin cap type No B22/25x26 and a clear pear shaped envelope with pip or pintel. The single filament, in the form of three loops, is attached to the lead in wires by the carbon tube method and supported by two molybdenum wires from a central stem or cane. The lead in wires are copper to platinum to nickel. The envelope is a hand blown vacuum type. Note the "metallised" carbon filament was first produced in 1904-5 and was a double heat treatment of a squirted carbon filament giving it a glassy or metallic finish. | 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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