Identification help please

[Whitebirch]

I have been cataloging a large electrical collection which, in turn, included a large collection of light bulbs. I have one bulb that I simply cannot identify, though I looks very familiar, I just can't put a name to it. What I'm trying to identify is the filament and the purpose. If any of you could help it would be greatly appreciated. Once the collection is cataloged it will make its way online and I will post the link to the collection at that time.

Thanks in advance for any assistance you may be able to provide.

Dana Twiss
CMP Project Curator
Maine Historical Society
Portland, Maine

[James]

It looks as though this is an attempt to make a double-life lamp.  From the internal configuration it would seem that it has two separate filaments.  When new, only one of these filaments will operate.  However once that has burned out, the high voltage present across the internal mica plate will cause the second filament to be connected and thus give the lamp a second life.  I have not seen this kind of construction before from any manufacturer.  Similar products existed in Europe during the 1920-1940 period, but those had an external switch on the base to manually connect the second filament.  Are there any other markings on this lamp?

[Whitebirch]

Thanks for the reply. Unfortunately there are no markings at all on this lamp. It is part of a larger collection of lamps that we received as part of the Central Maine Power collection when their historical committee was disbanded. More of the collection can be found at http://mainehistory.pastperfect-online.com/

[Chris Kocsis]

I got one of these from another collector and just lit it, bringing it up gradually with a variable transformer.  Both filaments light at the same time.  I raised the voltage slowly to 110 and then one filament started blinking off and on.  This bulb is a blinker with a bimetallic strip on one filament.  The blinking was irregular but probably becomes more regular at 125 volts.