 Maybe 10 minutes. It was really expensive. An entire day's wages got you the equivalent of 10 minutes of light from a kind of dim light bulb. Economists talk a lot about productivity, how much one person can produce with a day's labor. And back then, the answer was not much. I mean, everything was hard. Growing food was hard. Making candles, for instance, took hours. And it used up fat. Fat, which, by the way, was expensive because raising animals was hard.