For the fatigued among us, there are few greater simple pleasures in life than waking up momentarily in the middle of the night, looking at a clock, and realizing that you have a few hours left before you have to wake up. Being able to return to sleep is a luxury few of us are willing to give up.

But what if you couldn’t see your clock?

This not-so-hypothetical was the norm a few centuries ago, before the invention of safe light sources allowed people to see their surroundings at night. While mechanical clocks were common by the 15th or 16th century, illuminated clock faces or numerals post date the invention of the light bulb. In the 17th century, if one woke before daybreak, determining what time it was required a lot more than simply rolling over and peeking at your alarm clock or cell phone. In most cases, our late-hour waker would have to get out of bed, find moonlight or a candle (and a fire source), and effectively, start their day — just to learn that he or she could have slept another few hours.

Frenchman M. de Villayer would not settle for this.

Villayer developed a special clock to allow him to quickly determine the time at night without fully coming to his senses. Or, rather, by only relying on his senses of touch and smell. As recounted in the books “Clocks and Culture” by Carlo M. Cipolla (per the New York Times, here) and “The Discoverers” by Daniel J. Boorstin, Villayer built a “spice clock” of sorts. At night, he could feel around in the dark for the clock’s hour hand. Each nighttime hour had a different, easily distinguishable spice near where the arrow hand would point. Villayer would simply dip his finger into the spice, taste it, and know with certainty what the approximate hour was. As Boorstin notes, “[e]ven when [Villayer] could not see the clock, he could always taste the time.”

Bonus fact : According to a 2006 report in the Economist, “a typical microwave oven consumes more electricity powering its digital clock than it does heating food.” While heating food requires as much as 100 times the power as running the clock does, the Economist notes that the microwave heats food less than 1% of the time while the clock is typically always running. Therefore, in total, the clock uses up more electricity.

From the Archives: Power Play: Two different ways to bring illumination, safely, to areas where it is lacking.

Related: “Clocks and Culture” by Carlo M. Cipolla (4 stars on 7 reviews) and “The Discoverers” by Daniel J. Boorstin (4.5 stars on 95 reviews).