Light is a fabulous example. In England, artificial lighting was twenty thousand times more expensive circa AD 1300 than it is today. But when Ridley extended the equation and examined how the amount of light bought with an hour’s work (at an average wage) has changed over the years, there is an even bigger savings: Today [light] will cost less than a half a second of your working time if you are on the average wage: half a second of work for an hour of light! Had you been using a kerosene lamp in the 1880s, you would have had to work for 15 minutes to get the same amount of light. A tallow
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