Painting Depicting Thomas Edison and his assistants During the ‘Death Watch’ from 19 to 21 October.

Painting by Dean Cornwell

Sources vary as to how long Edison’s first successful electric lamp actually burned and the exact dates the event occurred.  According to some sources, the original bulb was ready for trial on the evening of Sunday, 19 October 1879.  A few of the doubtful of Edison’s team were said to have jokingly placed bets on how long the lamp would burned.  Most, as it turned out, lost their bets as the fragile filament burned reliably with a soft but constant reddish glow for more than 40 hours from that evening until well into the early afternoon of Tuesday, 21 October.  Finally, on that afternoon, Edison, seeking to increase the brilliance of the lamp, successively jacked up the current so that the filament grew brighter and brighter until it burned out.  But whether the first electric lamp lasted for 13 ½, 14 ½, or 40 hours, it was clear during that month of October, the era of incandescent lamp lighting was finally arriving.

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