[User23]

I wonder how they came up with that 1750 BC figure of 400 hours of work for one hour of light. Any ideas? It sounds ridiculously high, so I assume I'm missing something. What are they even talking about? Olive oil or tallow lamps? Firewood? Something else?

[hutzlibu]

"One hour of light (referred to as the quantity of light shed by a 100 watt bulb in one hour) cost 3200 times as much in 1800 in England than it does today"

Oil lamps are not so bright, and you would need lots of them to reach the same brightness as a 100 watt bulb.

In other words, they still had light, but not so much and not so often.