Dorrin K Mace, Horologost

Dorrin K Mace, Horologost
The Clock Man in a pensive moment

Sunday, April 22, 2012

The Sand Clock or Hourglass

The hourglass has also been called a “sand clock“.  Works on the same principle as the clepsydra. With clepsydra (AKA water clocks), water moves from one vessel to another or leaks out of a vessel at a precise rate. How much water is present in a second vessel or remaining in the only vessel indicates the time depending upon the design of the clock. Water clocks date as far back as 1500BC.
Some people date “sand clocks” to 1300AD when requests for hourglasses started showing up on shopping lists for ships. The hourglass was important for shipping. Water clocks and pendulum clocks aren’t reliable on ships because they need to be stable to keep time accurately. Hourglasses can be suspended from a hook and the swaying of a ship doesn’t interfere very much with the movement of the sand. Additional support for the hourglass being invented in the 1300s is that an hourglass is featured in Lorenzetti’s work “Allegory of Good Government” which was created in 1338. Some people say this is the earliest artistic representation of an hourglass. That puts the hourglass being invented at the same time as the mechanical clock and that doesn’t pass the smell test. (if it smells odd don't jump to use it)
Ancient Egyptians, ancient Greeks, and ancient Romans, all had the technology, knowledge, and supplies needed to create a sand clock. The idea that technology seemed to stand still from 1500BC to 1300AD just doesn’t make sense.
According to Knight’s American Mechanical Dictionary (copyright 1817): “The sand-glass was derived from or suggested by the clepsydra.” The dictionary goes on to say, “On an ancient bas-relief in Rome an hour-glass is placed in the hands of Morpheus. Athenaeus says that the ancients carried portable hour-glasses with them.”
Charles Dickens (yes, the Charles Dickens) made note of the same depiction of Morpheus in the which an hourglass can be seen in his nonfiction weekly journal, “All the Year Round” (volume number: X; copyright 1873). “No one knows at what period these time treasures were introduced. In a basso-relievo at Mattei Palace, presenting the marriage of Thetis and Peleus, Morpheus appears holding an hour-glass in his hand. This shows, at any rate, such implements were known in mythological days of Greece.”

An artistic depiction of an event isn’t evidence of technological levels at the time of the event. It’s evidence of technological levels at the time of the creation of the artwork.  Attempts to date the Mattei Palace came across a tidbit of information that puts the palace construction around 1191. We’re unsure of the accuracy of that date. The famous “turtle fountain” on the grounds of the Mattei Palace dates back to the 1500s. The turtles themselves weren’t added until the 1600s. The idea was to date the wall that held the bas-relief, but that turned into another dead end.
Numerous horological websites state that the hourglass dates back to ancient times. We know that ancient societies used oil lamps, candles, as well as clepsydra to mark time. It stands to reason that they would also use sand. Some history websites mention that hourglasses were used to time Senator’s speeches in ancient Rome. The book “Ancient Inventions” states that the Senators used clepsydra for that purpose not sand-based timepieces. The Senators would use a wax plug to temporarily pause the “clock” when their speeches were interrupted. Sand would cling to such a plug and with several uses the accuracy of the hourglass would be questionable.
By the 1300s hourglasses were so common that they were a staple on ships and were used symbolically in artwork. It takes time for a symbol to seep into culture and to be used symbolically. The symbolism of the hourglass seems to span several different cultures. That would also take a lot of time. We can’t point to any definitive piece of evidence, but 1300 seems way too late for the creation of the hourglass.
The hourglass is a technological equivalent of the ancient water clocks and we believe they date back that far.

The sand used in a decent hourglass isn’t regular sand. Sometimes it’s not even sand. Typically, sand is too angular to pass evenly through the neck of an hourglass. Angular sand will also wear away at the glass and slowly widen the neck which results in an inaccurate timepiece. Polished, dried, and rounded sand is sometimes used. Powdered marble and silica is sometimes used also. A few sandglasses actually contain tiny glass beads or shot instead of sand.
Some hourglasses were quite elaborate and fit the name “sand clock” better than “hourglass”. Some sand clocks were a series of hourglasses that could be flipped independently. Some would mark the quarter and half hour while others would mark a whole hour or two hours. As previously mentioned, hourglasses were used on ships to help mark the passage of time while at sea. Sailors and pirates used hourglasses in a few different ways. One way was the “watch glass“. This was an hourglass that would sound a bell every half an hour so that the crew could keep track of time. Sailors also figured out how to determine their speed with an hourglass. A knotted piece of rope with a wood chip attached at the end would float out from the stern of the ship. An officer would use a small sand clock to mark time between the knots (between 15 and 30 seconds depending upon the culture). This is the origin of the nautical term “knots” as in “knots per hour”.
Some hourglasses are called “pulpit glasses“. These were hourglasses (some measured two hours) that were kept at the lectern of the sanctuary. When the priest would deliver their homily or the pastor would deliver their sermon, the hourglass helped prevent anyone from becoming verbose.  Some people still use hourglasses for games and as egg timers in the kitchen.  Hourglasses have been with us for centuries and have a colorful place in human history.

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