Edison GEM Light Bulb

This is an original Edison GEM bulb. The smaller GEM bulbs were dropped from the market in 1917, meaning this bulb is at least 102 years old (as of 2019). GEM bulbs used a filament that was 25-30% more efficient than the carbon filaments used in earlier bulbs (they gave more light and used less power) but were later left in the dust by the much superior tungsten filament, which appeared in 1907 and was in widespread use for the next hundred years. In the beginning, GEM light bulbs had twin hairpin filaments in series, but were later changed to a single continuous filament (like on this bulb) in 1909. See my 187 watt GEM bulb with twin hairpin filaments. The higher wattage GEM bulbs disappeared first, the smaller sizes were produced until 1917. The GEM filament is the work of Dr. Willis R. Whitney.

Westinghouse also made its own version of the GEM bulb, which was sold under the name "Westinghouse Metallized". It is interesting to note that GEM filaments are very springy, much more so than normal carbon filaments, and I suppose this extra flexibility might have made them more resistant to vibration. They appear more silvery than carbon filaments, and appear to be a thinner gauge for the same wattage.

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