BulbCollector Forums
BULB DISCUSSION BOARDS => Antique Bulb Discussion => Topic started by: James on July 28, 2019, 02:10:11 pm
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Recently I came across an example of an early inside frosted (http://lamptech.co.uk/Spec%20Sheets/IN%20WC%20GE-Edison%20120-50A21IF-E26.htm) lamp with the Edison Mazda brand, and since the internal date markings are not visible I would like to try to determine its date of manufacture. Since it is inside frosted, it must be later than 1925 when that type of lamp was first introduced. I thought that it may be possible to identify the last possible date by knowing when GE stopped using the Edison Mazda brand, but realise that I don't actually know when that happened - perhaps some other members may have details about this?
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Surprisingly there is rather a lot of information in old lighting books and journals about GE's takeover of National Mazda and the requirement to re-name that as the National Lamp Works of GE, but I have also not been able to find a precise date of when National Mazda was dropped and replaced by GE Mazda.
By looking at old advertisements, I have not found any National Mazda references after 1931, but Edison Mazda appears to have been in use as late as 1935. Meanwhile there are GE-Mazda branded advertisements appearing from 1930 onwards.
If anyone might be able to more precisely identify these dates, it may be of great assistance to help us identify the likely production dates of older lamps.