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Description: | TO BURN CAP DOWN MADE IN ENGLAND 250V 1000W OSRAM QA A1/59 (acid etched on the glass envelope). ZX (written in black on the cane). MANU General Electric Company Limited of England. circa 1955 England DES after SWAN,Joseph,Wilson,Sir. 1878 Newcastle-Upon-Tyne England This is a 250 Volt 1,000 Watt class A.1. projector lamp with a prefocus end cap and a clear tube shaped envelope which allows tungsten to condense at the top of the tube without affecting the optical properties of the tube in the area of the filament. The top of the tube is also blackened. It was intended to be mounted vertically and burned cap down The single ductile tungsten bi planar grid coiled filament is welded to the nickel-nickel/iron-copper composite lead in wires. It is supported by a lower set of five stout molybdenum wires and an upper set of four wires mounted on a central glass cane. Both sets of 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 type without a pintel or pip. The lamp was filled with a nitrogen or nitrogen/argon mix through a hole in the base of the cane This tube was a spare intended for use in a lecture theatre 35mm Aldis projector (the cellophane tape anotated by W.I.P. 3.6.59 has been discarded). It would have probably been operated in conjunction with a mirror set such that the reflected image of the filaments would appear between the filaments of the lamp efectively producing a solid filament type lamp. The carton for this lamp is in a cardboard box on top of SCI:1 | 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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