How long did the first light bulb stay lit?

Accompanying photograph shows the first electric bulb made by Thomas Alva Edison. He had used thick cotton thread as filament in his bulb which, after burning, had partially taken the form of carbon.

The bulb gave light continuously for 48 hours 40 minutes after being switched-on on October 19, 1879. Ultimately the filament of the bulb snapped on October 21, 1879. Therefore, the latter date is considered to be the date of invention of the electric bulb.

More reading:
Incandescent light bulb (Wikipedia)

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