Sleepy History - Timekeeping

Episode Date: May 11, 2025

Timekeeping—the ancient art of measuring the moments that shape our lives. From sundials and water clocks to mechanical marvels and atomic precision, humanity’s quest to track time has driven innovation and connected civilizations. But how did this journey begin, and how has our understanding of time evolved? Tonight, explore the fascinating history and ingenuity of timekeeping, as you drift into a peaceful and timeless sleep.Narrated by: Simon MattacksWritten by: Alexandra TurneyAbout Sleepy History Delve into history's most intriguing stories, people, places, events, and mysteries, delivered in a supremely calming atmosphere. If you struggle to fall asleep and you have a curious mind, Sleepy History is the perfect bedtime companion. Our stories will gently grasp your attention, pulling your mind away from any racing thoughts, making room for the soothing music and calming narration to guide you into a peaceful sleep. Want to enjoy Sleepy History ad-free? Start your 7-day free trial of Sleepy History Premium: https://sleepyhistory.supercast.com/Have feedback or an episode request? Let us know at: slumberstudios.com/contactSleepy History is a production of Slumber Studios. To learn more, visit www.slumberstudios.com.

This is Sleepy History. Sleepy History is a production of Slumber Studios. To listen ad-free, get access to bonus episodes, and support the ongoing production of this show, Check out our premium feed. What time is it? If you want to know, you can check your watch, your phone, your computer. The time is all around us. But for thousands of years, that wasn't the case. If people wanted to know what time it was,

they had to consult a public sundial or a water clock, and these weren't always reliable. Tonight, we'll be exploring the development of timekeeping devices throughout the centuries. Along the way, we'll discover the ancient origins of the 24-hour day and the surprising story behind the wristwatch, once considered a passing fad. So just relax and let your mind drift as we explore the sleepy history of timekeeping. When it comes to early civilizations, some evidence has unfortunately been lost to time. But from the evidence we have, it seems that humans have always been fascinated by the

passing of time, making their best attempts to track it. In the Ice Age, more than 20,000 years ago, hunters in Europe made markings in sticks and bones. This may have been their way of tracking the phases of the moon. Indeed, for thousands of years, the only way people could keep track of time was to look at the sky. They traced the movement of celestial bodies like the sun and moon. Some people believe that Stonehenge, the prehistoric stone circle in England, may have been an early timekeeping device.

There are many different theories about the intended function of Stonehenge. But one popular theory is that it was built as a solar calendar. The structure seems to be oriented towards the sunrise and could have been used for tracking annual events such as the summer solstice. According to a recent study, the ring of 30 upright stones might have represented the days in a month. of 30 upright stones might have represented the days in a month. However, even if Stonehenge was used as a kind of astronomical observatory, it didn't really resemble a timekeeping device in the modern sense. The first known instruments designed specifically to measure time, such as sundials, came thousands of years later.

We don't know exactly when the sundial first appeared, but it was most likely in ancient Egypt, around 1500 BCE. The first sundials would have been very rudimentary, just stakes in the ground. The length and direction of the shadow indicated the time. By 1300 BCE, the Egyptians had come up with something a little more sophisticated. A limestone sundial that divided daytime into 12 parts. This artifact was discovered in the Valley of the Kings in an area that once housed construction workers.

One theory is that the sundial was used to keep track of their work hours. What's interesting about this particular sundial is the fact that it's divided up into 12 sections. It's evidence that the ancient Egyptians used the duodecimal system, a numerical system based on the number 12. We can see echoes of this in the system we use today. Our 24-hour day is split into two cycles of twelve. So, our modern-day method of timekeeping can be traced back to the ancient Egyptians.

While it was refined by later cultures, essentially it began in Egypt. This raises another question. Why did the Egyptians use the duodecimal system? If you think about it, it probably seems a bit arbitrary. Why twelve? Well, interestingly, the Egyptians weren't the only civilization to use the duodecimal system.

The Babylonians also used it for timekeeping, as did people in ancient China. According to one theory, the duodecimal system may have originated from finger counting. If you use your thumb as a pointer and count the three segments on each of your four fingers, you can reach 12. It's fascinating to consider that this might be the origin of our modern-day clocks, something as simple and universal as people counting on their fingers. Now let's get back to the Egyptians and their sundials. These proved to be a convenient way of measuring time, and later became more precise and sophisticated.

Obelisks were also used as timekeeping devices, a bit like public clock towers. They cast a moving shadow that acted as a kind of sundial, indicating the time of day. But this wasn't their primary function. Obelisks were built as monuments and were often designed to honor a king or a deity. For everyday timekeeping, the average Egyptian probably relied on humble, smaller-scale sundials. However, these devices came with some obvious disadvantages. They were all but useless on overcast days, and they couldn't be used at night.

at night. The time keeping at night, one solution was the merket, which was used from around 600 BCE and possibly earlier. The name merket meant instrument of knowing. It consisted of a horizontal bar with a plumb line. When used together with a corresponding tool, like a sighting tool or a second merket, this device could establish a meridian, a north-south line. The user could then track the movement of the stars, noticing when they crossed the meridian. And from this, they could determine the time.

The Merket was a clever, remarkably accurate tool, but this too had its limitations. It wasn't exactly user-friendly, and it had the opposite problem to the sundial. It could only be used at night. This brings us to another invention, the water clock. Both the Babylonians and the ancient Egyptians used this device to measure time. The oldest physical evidence we have of a water clock dates back to around 1400 BCE, about a century after the first known sundials in Egypt. Early water clocks were simple devices. A stone vessel was filled with water and a small hole at the bottom

allowed it to drain slowly. Inside the vessel were markings. By looking at the water level, the user could track the passage of time. The advantage of these water clocks was that they worked at all hours of the day. But there were limits to their accuracy. The flow of water was difficult to control, and the water itself was affected by factors such as temperature and humidity. Nonetheless, the water clock remained popular

in ancient Egypt, Greece, and Rome. And over the centuries, it became increasingly sophisticated. The Greeks called the water clock the Klepsydra, or water thief. A particularly impressive one was constructed in Athens in the first century BCE. A marble tower, known as the Tower of the Winds, stands to this day in the Roman Agora of Athens. As well as once featuring a wind vane and various sundials, it also housed a large large mechanized water clock.

The water likely came from a spring on the Acropolis. Given its prominent position, it's likely that the Tower of the Winds functioned as a kind of public clock tower. However, it's not clear how the average Athenian would have been able to use the water clock to tell the time. They may have had to go inside the tower. And although this particular clock was more sophisticated than early models, it still would have had limited accuracy because of its reliance on water. Still, the existence of the Tower of the Winds and its water clock is telling.

It shows how timekeeping was valued in ancient civilizations, becoming the focus of elaborate monuments. Increasingly, people wanted to understand and acknowledge the passage of time. It's now time to turn our attention to another part of the world, China. In China, people also used water clocks for timekeeping. Some devices were incredibly intricate, such as a legendary clock tower in the city of Kaifeng.

It was designed by the polymath Su Song in the 11th century. Standing at almost 40 feet high, Su Song's impressive tower was a clock and calendar in one. In addition to telling the time of day and the day of the month, it also tracked celestial movements which were displayed on a rotating sphere. There were also some fancy decorative features, like a changing parade of mannequins who rang bells and gongs. But from a mechanical point of view, the water clock was particularly innovative for its

use of an escapement mechanism. The main part of the clock was a huge wheel with scoops. Each scoop would fill with water, then pivot and empty, turning the wheel at a steady pace. The flow of water was regulated by a tank, which helped to maintain precision. It was a remarkable technical achievement. Su Song was ahead of his time, as clocks of similar complexity wouldn't appear in Europe until a few centuries later. Su Song's clock must have been quite a sight to behold.

Unfortunately, however, it was dismantled during the invasion of Kaifeng in 1127. The invading army took the pieces of the clock tower back to Beijing, or Yanjing as it was known at the time. But, unsurprisingly, the clock turned out to be too complex to reassemble. Water clocks of varying levels of complexity were widely used in China, but they weren't the only form of timekeeping. Another intriguing device was the incense clock. It first appeared in China around the 6th century, that may have first originated in India. The basic concept of an incense clock is quite simple.

It measures the passing of time by the rate of combustion, in other words, how long it takes a stick of incense to burn. However, many incense clocks were intricate creations. Some required slow, careful preparation, as the user placed incense or pieces of scented wood along a trail. The longer the trail, the longer it burned. Essentially, the clock was a scented timer. Some incense clocks could also be used as alarms.

For instance, there's a beautiful Chinese clock from the 19th century. It's made from wood and metal and shaped like a long dragon. Several threads were stretched across the body of the dragon. As the incense burned, the threads broke. This allowed the balls attached to the threads to fall into a metal container below, making a clinking noise, a gentle alarm. In Asia, incense clocks remained popular for a long time, and not just because of their aesthetic appeal.

For centuries, they were also much more affordable than mechanical clocks, which were mainly owned by wealthy families. Into the 20th century, coal miners would use incense sticks to measure time while underground. And in Japan, geishas used incense timepieces to keep track of how long they had spent with customers. Before we move on to the mechanical clock, there's one more type of old-fashioned timekeeping that deserves a mention – the hourglass. The exact origins of the hourglass are unknown, and the earliest evidence we have of its existence is surprisingly recent, an Italian painting from 1338. In the Allegory of Good Government by Ambroggio Lorenzetti, a fresco panel features a woman holding what appears to be an hourglass.

This object became an enduring symbol, appearing in countless Western artworks. There's something rather poignant about the hourglass as a visible representation of the passing of time. as a visible representation of the passing of time. While it's possible that the hourglass existed long before Lorenzetti's painting, the evidence is lacking. Interestingly, if the hourglass was indeed invented around the time of the painting, that would make it a more modern invention than the mechanical clock. The mechanical clock first appeared in the late 13th century, or there's no evidence for the hourglass until the 14th century.

This probably seems surprising. The hourglass seems like one of those ancient, mysterious objects that's been around since the beginning of time. And indeed, what the hourglass lacked in accuracy and sophistication, it made up for in symbolic power. However, the hourglass did in fact have an important practical use. From written records, we know that the marine sandglass was used on European ships from the 14th century.

These were resilient, easy-to-use instruments that could be used not only to measure time at sea sea but also to help with navigation. Unlike water clocks, the accuracy of marine sunglasses wasn't affected by the movement of the ship. And compared to mechanical clocks, they were cheap and simple devices. Still, marine sand glasses had to be carefully built and calibrated, taking into account factors such as the quality of the sand. A tight seal was also essential to prevent moisture from entering. to prevent moisture from entering.

But in the right conditions, these instruments could be reasonably accurate, and they were a staple on ships well into the 19th century. On land, hourglasses were also used in churches, so the priest or vicar could time the length of their sermon. Another advantage, perhaps, was the silence of the hourglass, compared to a noisy ticking clock. And again, there was the hourglass's symbolic nature. As people in the congregation watched the falling sand, maybe they were moved to reflect on the fleeting nature of time, and in some cases perhaps on how much longer the sermon would last. Interestingly there's also a religious element to the invention of the mechanical clock.

It first appeared in medieval Europe, and in part it seems to have originated out of monastic routine. Catholic monks lived by a strict routine, which often involved seven prayer sessions a day. They needed to have some idea of time in order to stick to their schedule. In the gloomy climate of northern Europe, sundials obviously weren't an option. And neither were water clocks, as the water would freeze in winter. Above all, what the monks needed was something that would wake them up for early morning prayers – an alarm clock.

Some of the earliest mechanical clocks were designed to sound a bell at certain times. This explains the etymology of the word clock. The origins can be traced back to the medieval Latin word clocka meaning bell. If you think about it, these origins make perfect sense. The human need to know the time is based on our activities, the things we have to do at certain points in the day. It's especially important for people living in structured communities,

like monasteries, where everyone needs to be in sync. like monasteries, where everyone needs to be in sync. The exact mechanisms of the first clocks are unknown. What we do know is that from the late 13th century onwards, clocks began popping up in religious institutions in England, France, and Italy. Over the following centuries, the development of the mechanical clock took place mostly in Europe. The spring-driven clock was invented in the 15th century and the pendulum clock in the 17th century. You might be wondering how do mechanical clocks work?

Well, the specific mechanism varies depending on the type of clock. But, generally speaking, a mechanical clock features an oscillating mechanism, such as a balance wheel or pendulum. It also has an escapement mechanism which counts the beats. The act of winding a mechanical clock gives it the energy it needs to run. Over the years, clockmakers continued to strive for ever greater accuracy. Clockmaking was both a science and an art, and of course, a business. Early mechanical clocks were expensive. It wasn't until the 19th century and the age of mass production

that the average family in Europe could afford to own one. Before that most people would have relied on public clocks such as clock towers. And if they were lucky enough to own a clock it would have been something to treasure. Think of the grandfather clock, for example, a beautiful object that often became a family heirloom. Compared to earlier timekeeping devices, mechanical clocks were much more reliable and easy to read. They also became much more widespread over the centuries, a common sight in both public places and homes. In addition, clocks were becoming increasingly accurate. These developments helped to create a shared sense of time across large populations.

Essentially, the mechanical clock did something its predecessors couldn't. It enabled the standardization of time. This, in turn, made other cultural developments possible. The Industrial Revolution, for example. In order for factories to function and trains to run, people need to know exactly what time it is. For a medieval farmer, it was enough to look at the sky and organize the day around the changing light.

But for a 19th century factory owner, it was essential to keep track of time and to know that everyone else was on the same schedule. You could even say that the mechanical clock was transformative. It helped to lay the foundations for modern industrial society and made it so much easier for capitalist economies to thrive. It's no coincidence that these days CEOs tend to have strict time-based schedules. They know exactly what they'll be doing at 8am, 9am, and so on. As they say, time is money.

Now let's go back in time for a moment. At some point in the 16th century, people in Germany began wearing portable timepieces, otherwise known as the watch. Peter Henlein, a clockmaker from Nuremberg, is often given credit for inventing the watch. Although he may not have been the first, he was certainly a pioneer. Enlien's path to clockmaking was an unusual one, to say the least. He was originally a locksmith. But when a fight with a fellow locksmith ended in the other man's death, Henlein sought asylum in a monastery.

Monasteries were often centers of learning. This particular institution in Nuremberg specialized in scientific and astronomical studies. It's thought that Henlein honed his clockmaking skills while staying at the monastery. And when he left, he launched his career, crafting portable clocks for wealthy customers. These spring-powered brass clocks were beautiful creations, worn prominently as pendants. A customer who spent fifteen florins, or thousands of dollars, on a timepiece would have no doubt wanted to show it off. By the 17th century, however, pocket watches had become more common than pendants. It's thought that fashion played a part in this shift.

King Charles II of England was a fan of the waistcoat. And after his public championing of the garment, it became increasingly fashionable in Europe. Waistcoats had pockets, the perfect place to put a watch and keep it safely tucked away. These days, of course, we think of the watch as something to be worn on the wrist. we think of the watch as something to be worn on the wrist. When we use the word watch, what we actually mean is wristwatch. The wristwatch is thought to have originated in the 19th century. In 1812, the French watchmaker Abraham Louis Bruguet designed a wristwatch for Caroline Bonaparte, sister of Napoleon and Queen of Naples.

It's possible that wristwatches existed prior to this. Queen Elizabeth I of England is said to have received a bracelet watch as a gift in 1571. However, as a practical timepiece, the wristwatch is generally considered to be a 19th century invention. For many years, wristwatches were worn almost exclusively by women. They were seen as elegant accessories. In the early years, wristwatches were worn almost exclusively by women. They were seen as elegant accessories, a bit like bracelets. Men preferred their pocket watches. But towards the end of the 19th century, things began to change. For men in the military, keeping track of time was essential,

as it allowed them to synchronize their maneuvers during battle. But whipping out a pocket watch in the heat of battle wasn't exactly ideal. They needed to be able to keep their hands free. From the 1880s onwards, soldiers in the British Army began strapping watches to their wrists. The wearing of these watches, which were often modified pocket watches, helped to change the image of the accessory. The wristwatch was no longer just a feminine decorative object, it could also be masculine and practical.

In 1904, the French watchmaker Louis Cartier designed a special watch for his friend, the Brazilian aviator Alberto Santos Dumont. As a pilot, Santos Dumont needed a timepiece that was reliable, practical, and easy to read, something he could glance at quickly while flying. The Cartier Santos watch, which is still produced to this day, is generally considered the first purpose-built men's wristwatch. With soldiers and pilots wearing watches on their wrists, the trend soon took off. watches on their wrists, the trend soon took off. By the end of the First World War, the wristwatch had virtually replaced the pocket watch. In 1916, the New York Times acknowledged that wearing a bracelet with a clock on it was no longer, in their words, a silly-ass fad.

The wristwatch was here to stay. And with brands such as Patek Philippe and Rolex, some watches became a luxury item. But of course, while the watch could be a status symbol, it wasn't just for royalty and aristocracy. Unlike the early clocks and watches, 20th-century wristwatches were something that most people could realistically afford. Those who had the money could splash out on a Rolex. But affordable watches became readily available too,

and soon they were something that almost everyone owned. Timepieces were more accessible than ever. If you think about it, it's quite a change. A thousand years before, people had been reliant on public sundials or water clocks. A few hundred years before, clocks were luxury items with a privileged few. And by the mid-20th century, it was standard for people to have a personal timepiece, their very own watch. Most of the great innovations in timekeeping took place between the 13th and 19th centuries. However, the story is far from over, as the quest for ever greater accuracy continued,

and continues to this day. Now let's take a look at quartz. If you own a watch, there's a good chance it has a tiny quartz crystal inside. Quartz is a mineral which has piezoelectric properties. This means that when the quartz is subjected to mechanical stress, it generates an electrical charge. In quartz watches, this effect works in reverse. An electric current, which comes from the watch battery, causes the quartz crystal to

vibrate. This vibration creates electric signals, which are used to keep time. Because of the consistent frequency of these vibrations, quartz watches are much more accurate than mechanical timepieces. To put in context, a quartz watch might gain or lose just a few seconds per month. Whereas a mechanical watch can gain or lose around six seconds in a day. That's a significant difference. The first quartz clock was created in 1927, and over the following years, their impressive accuracy made them popular in laboratories

and observatories. Early quartz clocks were large and bulky, but in 1969 the Japanese company Seiko began producing quartz wristwatches. The first ones weren't cheap, costing the equivalent of several thousand dollars. But in the 1970s, affordable, battery-powered watches started to become widely available. While quartz timepieces are more accurate than mechanical ones, that's not to say they're superior necessarily. Some watch lovers prefer mechanical pieces, appreciating the elegance of their design and the fact that they need a bit of care and maintenance.

It might be said that a mechanical watch has more character than a quartz one. Still, scientists and engineers tend to be more interested in the cold hard facts. So, after the invention of the quartz watch, they looked into creating something that was even more accurate. And that led to the invention of the atomic clock. Now, to understand what an atomic clock is, let's remind ourselves of how clocks in general function. Basically, a clock consists of a mechanism which oscillates or vibrates, plus a device that counts the beats and shows the time. In a mechanical clock, the oscillating mechanism could be a pendulum, for example. In a quartz watch, as we've just seen,

the mechanism is the quartz crystal that vibrates. But both pendulums and quartz crystals have a limitation. They're man-made. No two timepieces are perfectly identical, and even small variations can cause them to drift slightly over time. So, these timepieces can never stay completely in sync. They're always unstable to some extent, gradually losing or gaining seconds over time. some extent, gradually losing or gaining seconds over time. So in order to maximize accuracy, we need to measure the beats of something that's

not man-made. Something fundamental, such as atoms. Atomic frequencies offer pure, stable beats, the best in the universe as far as we know. The idea of using atoms to measure time was first proposed in the late 19th century. But it wasn't until 1955 that a scientist, the English physicist Louis Essen, managed to create a truly accurate atomic clock. Since then, the accuracy of atomic clocks has continued to improve. It's no exaggeration to say that they're literally billions of times more accurate

than other kinds of clocks. As you may remember, a quartz watch can gain or lose a few seconds per month. But if an atomic clock had been running since the Big Bang, nearly 14 billion years ago, it would have gained or lost less than a second. Because of their extraordinary accuracy, atomic clocks are used to calibrate other clocks. But their use isn't limited to timekeeping. Atomic clocks play a part in everything from telecommunications to space navigation. And here's something to think about.

When you use GPS, an app like Google Maps for instance, your phone receives a signal from a navigation satellite. And what's on that satellite? None other than a high-precision atomic clock. It might seem like we've peaked in terms of accuracy, but the history of timekeeping is one of continual change and evolution, so it seems unlikely that we'll stop any time soon. The next development will probably be nuclear clocks.

These clocks, which would measure time using signals from an atom's nucleus, could potentially be ten times more accurate than atomic clocks. Still, accuracy isn't everything. Another trend we've seen throughout history is timepieces becoming smaller, cheaper, and more accessible. In the future, maybe it will be common for people to have their own atomic clock at home. Or an atomic watch perhaps. Another possibility is that timepieces could become smaller still. Rather than being an accessory, maybe they could even become part of our bodies. Instead of

learning to tell the time from clock faces, future generations might grow up with a new technology, something that allows them to know the time at all times. Right now, this might seem like science fiction, but just consider the leap from sundials to atomic clocks. How amazed an ancient Egyptian would be if they could see our current technology. Thanks to the efforts of generations of scientists, engineers and horologists, we've already achieved a kind of mastery of time. Or the illusion of it, at least. From phones to smartwatches, we're surrounded by an increasing array of highly accurate timekeeping devices.

They give us a feeling of control. The idea that time is something we can understand and manage. But if history teaches us anything, it's that we humans are obsessed with making progress. We're forever coming up with new, improved technology. So, a new kind of clock is surely on the horizon. You You You The You You You You You You You You You I'm going to go ahead and close the video. you