Answer: Water Bowls

Today we have readily (and cheaply) available time keeping devices that not only maintain accuracy over time quite well (a quartz-driven watch typically has less than a few minutes of time slippage per year), but can also be easily synced to atomic clocks (which keep standard, accurate time the world over).

Long before you could pick up a quartz-driven watch for a few bucks off eBay, however, things were distinctly less about crystal vibrations and atomic decay and more about physical movement. In fact, way back in Ancient Persia, the Persians had a time keeping device that was not only based on physical movement, but the particular material being moved was especially appropriate, on a poetic level, for its task.

In Persia, there were elaborate sloping underground channels known as “qanats”. These channels were used to move water from underground aquifers and distribute it to farmers for use in agricultural irrigation. To ensure each farmer received a fair share of the water they were due, it was important that accurate time be kept. Using a set of water bowls known as a “fenjaan”, the time keeper would fill a large bowl with water and then place a smaller bowl floating atop it. The smaller bowl had a little hole in the bottom and it would slowly—like a ship sinking into the ocean—take on water and sink to the bottom of the larger bowl. When this happened, the time keeper would note it and either mark the passage of a cycle with a stone or other small token placed in a jar, or signal that the water distribution should cease.

The use and management of the water clock was a very important element in Persian agricultural society and the bowl was typically kept on the top floor of a public house or a tower that could see out over the land (as well as easily see each sunrise and sunset). No fewer than three people were assigned to each water clock—the actual time keeper along with two managers to observe the process and oversee the administration of the clock and water.