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BULB DISCUSSION BOARDS => Antique Bulb Discussion => Topic started by: Ed Covington on March 20, 2001, 07:30:00 pm

Title: Information Desired
Post by: Ed Covington on March 20, 2001, 07:30:00 pm

Does anyone out there have references that describe the so-called "Siemens" seal? Was that design patented? I am aware of the mention made on page 205 of Arthur Bright's book.

Title: Information Desired
Post by: James on March 21, 2001, 09:02:00 am

Hi Ed,

I inherited a lot of very old Siemens material when the Thorn factory in Preston shut down in 1994.  Thorn took over the Siemens UK division in the 1940's and when they shut the Siemens factory on Strand Road everything was transferred across town to Thorn's Kent St factory.  But I am not quite sure what you mean by the Siemens seal.  Can you provide any more info on the date or type of seal, then I can sift through the old Siemens papers I have and will let you know if I have anything of relevance.

James.

Title: Information Desired
Post by: Ed Covington on March 21, 2001, 10:04:00 am

Thanks, James, you're always a source of hard-to-get information. If you'll look in my book on page 47 the Fig. E is, I believe, what is called the Siemens seal. I assume it was developed about 1888-1891. That's about all I can tell you. The move from the design from E to F was made, I believe, because attaching the filament to copper didn't work out too well.