The eternally optimistic data nerds at the libertarian Cato Institute's HumanProgress project recently highlighted a fun factoid to celebrate the longest day of the year: Back in the prehistoric era a person would have to gather, chop and burn wood 10 hours a day for six days straight in order to produce the equivalent light of a modern lightbulb shining for about an hour.
Today, the same amount of labor could light a room for more than 50 years. Those figures are courtesy of a 1994 paper by Yale economist William Nordhaus. He was seeking a measure that could compare standards of living across radically different time periods, and settled on lighting.
The first major improvements over open fires were, in Nordhaus' telling, oil-burning lanterns. Around the time of the Babylonian empire, circa 1750 B.C., 60 hours of labor could buy the equivalent of 88 minutes of today's light.
Then came candles, which dominated the interior lighting landscape until the 19th century. Sixty hours of work bought you 10 hours of tallow candlelight in Revolutionary War times.
Around 1880, Thomas Edison's incandescent electric bulbs meant 60 hours of work would translate to 72 hours of lighting.
By 1950, 60 hours of labor would light a bulb for nearly 1,200 days. Today, light is something most of us take for granted.
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