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Description: | OZON MADE IN HOLLAND (acid etched on the glass envelope with crossed lightning bolts trade mark). 250-30 (black stencil on the end cap). B (stamped or moulded in the base of the cane) MANU OZON between 1910 and 1922 HOLLAND DES after SWAN,Joseph,Wilson,Sir. 1878 Newcastle-Upon-Tyne England This is a 250 volt 30 Watt general lighting service lamp with a non standard Swan double contact bayonet two pin cap compatible with type No B22/25x26 and a clear bell shaped envelope with a pip or pintel. The single ductile tungsten squirrel cage filament is clinched to the nickel lead in wires. The union between the copper and the nickel is made by a short length of platinum in the base of the cane. It is supported by a lower set of nine fine molybdenum wires and an upper set of ten mounted on a central glass cane. The support wires are in the form of fine crooks.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 hand blown vacuum type with a pintel or pip. The bulb being evacuated via the pintel in the top of the envelope. | 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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