Projectors

For much of the 20th century, no office presentation felt complete without the whir of a projector. Primitive projection devices such as the “magic lantern” had existed since the 17th century, but projectors didn’t become a common tool until the mid-20th century. During World War II, the U.S. Army relied on overhead projectors for training, a practice that helped usher the technology into civilian life after the war.

Offices (and classrooms) quickly embraced the product. Overhead projectors relied on a lamp and a flat glass surface to cast clear transparencies onto walls or screens. They were used to share charts, diagrams, or notes, or even collaborate by writing on the transparencies in real time.Starting in the 1960s (or earlier for some bigger companies), slide projectors filled a similar, but more polished, role. Using 35 mm slides arranged in carousels, they became staples in flashy sales pitches, their signature clacking sound immortalized in the memorable Mad Men episode “The Wheel” in 2007.

By the late 1990s, digital displays and computer software such as Microsoft’s PowerPoint, with its familiar slideshow functionality, rendered both formats all but obsolete.

Punch Clocks

Punch clocks were fixtures in all kinds of workplaces through the late 19th and 20th centuries, from factories to retail stores and, of course, offices. They emerged during the Industrial Revolution, when expanding workforces and hourly wages made keeping track of time a growing necessity. In the late 1800s, inventors began developing mechanical time recorders that stamped the time an employee arrived or left onto a paper card, turning time into something that could be monitored and paid out.

By the mid-20th century, punch clocks had become nearly universal in the workplace, replacing the timekeepers who manually tracked employees’ hours. Wall-mounted units with knobs or levers and slots for inserting cards sat beside rows of time cards. Some models rang bells; others used different colored ink for employees who were punctual and those who were late. As digital technology emerged in the 1980s and ’90s, paper cards and mechanical punches were replaced with online timesheets and the now-ubiquitous swipe badges.

Carbon Copy Paper

Every time we copy someone on an email, we’re technically recalling a vintage office relic. The “CC” line traces its origins to carbon paper, once an essential tool for making duplicates of documents. Invented in the early 1800s and widely used by the end of the century, carbon paper was coated on one side with a mixture of black carbon and wax. It would be sandwiched between a piece of paper that was being written or typed on, and another underneath. Whatever text was on the top piece of paper transferred onto the page on the bottom — along with some smudges here and there. This was known as a carbon copy, the origin of “CC.” 

Modern photocopiers arrived in offices in 1959 when Xerox debuted its 914 model. While it was certainly revolutionary, the machine remained expensive — it sold at about $29,500 a pop, which is almost $330,000 today — and was prone to catching fire. Needless to say, carbon paper didn’t disappear overnight, but by the end of the 1980s, copiers were streamlined and printers were accessible to most workplaces. Today, carbon copy paper remains relegated to specialty stationery stores that cater to niche clientele.

Adding Machines 

Much to the chagrin of math teachers everywhere, arithmetic is something most of us outsource to a screen today. But before computers, somewhere between the abacus and the calculator was the adding machine. Early versions were imagined as far back as the 17th century, but reliable models didn’t appear until the late 19th century. In 1888, William Seward Burroughs, a former New York bank clerk (and grandfather of famed Beat writer William S. Burroughs), patented an adding machine that could accurately total long columns of numbers and print the results.

Burroughs called his machine the Arithmometer, and after gaining international attention at the 1900 Paris Exposition, it quickly took off. Within 10 years, an estimated 100,000 office workers in payroll, accounting, billing, and other departments counted on their adding machines. Electronic calculators arrived in the mid-20th century, and by the 1970s, microchip-powered devices made adding machines and their signature keystroke sounds a relic of the past.

Pneumatic Tubes

When The Jetsons debuted in 1962, it envisioned a world of futuristic conveniences such as robot maids and flying cars. One of the predictions for the year 2062 was that air-pressurized tubes would transport people like high-speed elevators. It wasn’t entirely science fiction: At the time, pneumatic tubes were quite common in offices, quickly ferrying documents, cash, and small parcels between rooms and floors.

A person would drop a cylinder into a tube, and, after traveling at an air-pressurized speed of 24 feet per second, it would arrive at its destination shortly after. Entire transactions could happen almost instantly, making the tubes both practical and a bit magical. In their earliest days in the mid-1800s, these networks were indeed conceptualized as realistic transportation for humans and vehicles. Ultimately, that proved an impractical feat. Today, pneumatic tubes survive primarily in hospitals or, famously, as a trash removal system at Walt Disney World.

Dictaphones and Dictation Rooms

There was a time when important office correspondence wasn’t emailed, but spoken out loud. Early recording devices such as the Dictaphone, trademarked in 1907, allowed voices to be preserved on wax cylinders or magnetic tape for later playback. Managers dictated their intended documents aloud and typists produced them on the page. Some industries, including medicine and law, even maintained dedicated dictation rooms. 

Word processors and personal computers began to disrupt this process in the late 20th century, putting drafting, editing, and formatting directly into the hands of the person composing the document. While dictation rooms have largely disappeared, dictation itself has not: Doctors and lawyers still rely on it today; only now, digital recorders and smartphone apps handle the transcription automatically, folding a once larger office workflow into a single device.

Why 911? 

In 1968, in response to growing calls for a single emergency number, the Federal Trade Commission and AT&T announced that they had decided on a new, universal three-number sequence for emergency calls: 911. The number was chosen to satisfy multiple criteria. Most importantly, it was short, easy to remember, and quick to dial. On the rotary phones used at the time, “9” and “1” were both relatively easy to find, even in the dark. Dialing 911 was also faster than the 999 used across the pond, as “9” takes slightly longer to dial than “1” on a rotary phone. With the numbers being at opposite ends of the dial, it also meant that accidentally dialing 911 was less likely. 

Another important characteristic in 911’s favor was its uniqueness — it had never been previously authorized as an office code, area code, or service code. According to the National Emergency Number Association, the choice of 911, purely on a technical level, “best met the long-range numbering plans and switching configurations of the telephone industry” at the time. 

In other words, 911 didn’t conflict with any existing or planned numbers, and could be programmed into existing switches without major overhauls, meaning it was a good fit for both the existing telephone infrastructure and the industry's plans for future expansion. What’s more, AT&T had already helped standardize numbers such as 411 (the number for directory assistance), allowing it to use the same preexisting telephone system infrastructure to process and route 911.

A Slow Rollout

For the public, 911 was brief, catchy, and very easy to dial. And for the telephone industry, it offered a relatively hassle-free implementation. Dialing 911 would access a central operator that then routed to local emergency services by mapping landline phone numbers to addresses (or today, using location data from your cellphone). The nationwide rollout, however, proved to be a slow process. 

The new universal emergency number was first dialed in 1968, but it took decades until most of the country could use it. One major obstacle was the fact that the new 911 number only worked through Bell System telephone companies — all of the nation’s independent phone companies, of which there were many,  were not included in the emergency telephone plan. Local jurisdictions also had to fund the infrastructure upgrades, and some of them simply didn’t think the cost was worth it. By 1976, only 17% of the population had access to the service, rising to just 50% a decade later. 

Eventually, however, 911 made its way across the United States, becoming arguably the most memorized and instantly recognizable number in the country. Today, around 240 million calls are made to 911 in the U.S. each year — more than 650,000 emergency calls every single day. 

Mechanical Clocks Followed the Shadow

By the 13th and 14th centuries, large mechanical clocks were appearing in churches and town squares across Europe. These early machines were crude by modern standards — powered by falling weights and regulated by simple mechanics — but they represented a major shift in how time was represented, because timekeeping was no longer tied to sunlight. Clocks could run indoors and after dark, offering a way to keep time that was independent of the sky.

Yet despite their mechanical innovations, these devices inherited the sundial’s sense of rotation. Early clocks typically used a single hand for the hour, and that hand moved in the same direction people had watched shadows move for generations. The mechanism might have been new, but the visual representation of time was familiar.

As Europe became a center of mechanical clock innovation, these conventions spread. When clocks were adopted in regions where sundial shadows moved the opposite way, the European standard still dominated. 

Portable Clocks Personalized Timekeeping

By the 16th century, timekeeping was no longer limited to public towers. Advances in spring-driven mechanisms allowed for smaller, portable clocks that became increasingly refined, making it possible for individual homes and businesses to keep track of the time. By the 18th century, timekeeping was even more personalized with the development of pocket watches, which grew in popularity as the Industrial Revolution progressed.

Watchmakers built their devices to match the familiar direction of tower clocks, which themselves echoed sundial motion. Even as designs improved — adding minute hands, then second hands, and increasingly accurate escapements — the direction of motion remained consistent. Clockwise became the established system across the growing global clockmaking industry.

Industrialization Standardized Clocks

By the 19th century, the rise of industrial production, global trade, and expanding railroads created an urgent need for standardized timekeeping. Trains depended on coordinated schedules. Cities needed synchronized clocks. And manufacturers needed consistent designs.

As time zones were adopted and cities aligned their clocks, the sweep of the hands became even more standardized. Mass-produced wall clocks, factory whistles, station clocks, and schoolroom timepieces all reinforced the same familiar clockwise direction. 

There Were Counterclockwise Clocks, Too

Over the centuries, counterclockwise clocks did appear here and there, though they remained rare. They were usually found in places where a local tradition of vertical sundials made the opposite motion feel natural. One famous example still exists today: the astronomical clock on the Old Town Hall in Prague. Its hands run counterclockwise, following the right-to-left direction of Hebrew script and echoing older local traditions. This unique timepiece shows how easily the convention could have developed differently.

While analog clocks have mostly been replaced by digital timekeeping, the familiar clockwise motion is now simply an artifact of Northern Hemisphere sundials and the fact that Europe became the birthplace of mechanical clocks. If clockmaking had first flourished south of the equator — where the sun’s shadows sweep the opposite way — our clocks, watches, and even our idea of what “forward” in time means might move counterclockwise instead.

Recording Sound on Paper

In 1857 — nearly two decades before Edison’s phonograph — Parisian printer and bookseller Édouard-Léon Scott de Martinville patented a device he called the phonautograph. Scott de Martinville was a self-taught inventor who was fascinated by how the human ear and voice worked together. In the era of early photography, he wondered: What did sound look like?

The phonautograph was his answer. The machine consisted of a large horn that collected sound, a stretched membrane that vibrated with the air pressure, and a bristle or stylus attached to that membrane. When someone spoke or sang into the horn, the stylus etched those vibrations onto a sheet of paper or glass coated in soot from a lamp flame, preserving the pattern of the sound waves.

Scott de Martinville’s goal wasn’t to reproduce sound, because he had no means to play the recordings back. Instead, he wanted to make sound visible, by creating what he described as a visual record of the voice itself. 

He imagined scientists studying the visual signatures of speech, singers analyzing their tones, and future generations reading the voices of the past like musical manuscripts. In his writings, he questioned whether one might “preserve for future generations some features of the diction of those eminent actors… who die without leaving behind the faintest trace of their genius?”

The First Voice Recording

In April 1860, Scott de Martinville used his phonautograph to capture a voice singing the French folk song “Au Clair de la Lune.” The following year, he submitted the resulting soot-covered tracing to the Académie des Sciences in Paris for preservation.

At the time, no one could hear it. The lines were a pattern of vibration, so their meaning was visible but inaudible. It wasn’t until 2008 that the phonautogram could finally be played. A team of audio historians from the First Sounds project and scientists from the Lawrence Berkeley National Laboratory used high-resolution optical scanning of the soot-marked paper to convert the waveforms into audible sound. By scanning the lines in high resolution, they were able to translate the visual waveforms into digital audio.

What emerged was the faint but unmistakable sound of a human voice singing “Au Clair de la Lune.” The 20-second audio was marred by distortion and irregular tempo, so researchers at first thought the singer was a woman or a child. But further analysis revealed that it was likely Scott de Martinville himself singing.  

Because Scott de Martinville’s phonautograph produced the first known physical record of sound vibrations, which has since been converted into audible sound, it is recognized today as the earliest recording of the human voice ever made. The 2008 breakthrough effectively rewrote the first chapter of sound-recording history.

Scott de Martinville died in 1879, unaware that his sound tracings would one day be heard. Yet through the efforts of modern historians and engineers, his silent tracings finally became what he had imagined — a way to preserve sound for future generations.

Two decades after the phonautograph, another French inventor, Charles Cros, theorized a way to reproduce recorded sound. In April 1877 — months before Edison’s phonograph — he deposited a sealed letter with the Académie des Sciences describing his paleophone, a device that could both record and replay sound. Cros never built his invention, but his idea of capturing and reproducing the human voice became a reality with Edison’s phonograph in 1877.

Test Cards Have Been Around Almost as Long as TV

Test cards date back to the 1930s, when the BBC used printed cards placed in front of cameras to help engineers align signals. The BBC’s first test card, used in 1934, was a simple black circle with a line underneath it. The practice caught on in the U.S. in the 1940s as commercial broadcasting expanded. These early test cards were often mounted on easels in front of studio cameras during off-air hours.

Black-and-white patterns featured radial grids, concentric circles, and crosshairs to reveal image distortion, framing errors, or technical noise. With the arrival of color broadcasting in the 1960s and ’70s, test patterns evolved into electronically generated images such as the SMPTE (Society of Motion Picture and Television Engineers) color bars to test for hue, saturation, contrast, and brightness. Today, the calibration and troubleshooting of broadcast signals are handled by specialized test-signal generators, though they are not broadcast to viewers.

Test Cards Became Cultural Touchstones

Some test cards became more than just technical tools — they evolved into pop culture artifacts. In the U.S., the RCA “Indian head” test pattern — featuring a Native American figure flanked by geometric markings — was created in 1939 and ran for more than two decades, becoming a kind of visual shorthand for early American television. CBS had its own “bullseye” test pattern, a striking design with concentric circles and resolution wedges used to check focus and sharpness.

Depending on where you grew up, you might remember a specific local station’s test card — one that not only included the TV channel number and the affiliate’s call sign but also the location it was broadcasting from. For instance, ABC affiliate WJZ-TV in New York featured the Empire State Building on its black-and-white test card in the early 1950s, giving the broadcast a distinctly regional identity. These static images became a familiar part of daily television viewing, connecting viewers to their local stations and communities.

Across the Atlantic, the BBC’s Test Card F became one of the most iconic test patterns of all. Introduced in 1967, it featured a young girl named Carole Hersee (daughter of BBC engineer George Hersee) playing tic-tac-toe with a slightly unsettling clown doll named Bubbles. Airing for thousands of hours between 1967 and 1998, Hersee’s face became the most-broadcast image in U.K. television history.

A Nostalgic Link to Early TV

For viewers of a certain age, test cards were an unofficial signal that the day was over. When the test pattern appeared, you knew it was time to turn off the TV and go to bed.

In the 1980s and ’90s, however, 24-hour programming took over. Infomercials, syndicated reruns, and late-night variety shows replaced those once-quiet hours. Cable, satellite, and eventually streaming made content seemingly infinite and calibration test patterns largely obsolete. Today, if a station goes off the air (usually due to weather or technical issues), you’re more likely to see a local station logo or a digital error message than a test pattern.

Even though test cards have mostly vanished from live broadcasts, they still crop up in pop culture as a kind of retro shorthand — an inside joke for those who know what they represent. On The Big Bang Theory, Sheldon Cooper’s SMPTE color bars T-shirt turned vintage broadcast tech into a fashion trend; the image has been widely reproduced and sold on everything from clothing to coffee mugs. 

Some of us who remember when test cards signaled the end of the TV viewing day still have a strange fondness for their eerie stillness. In a world of endless choices and the seemingly judgmental “Are you still watching?” prompt, test cards remind us of a time when television showed us everything it had to offer — and then signed off for the night.

The Underwater Exploits of Cornelis Drebbel

While it’s entirely possible that Alexander the Great used divers at Tyre, and possibly a rudimentary diving bell, it’s hard to give him credit for the first true submarine journey. That honor is more correctly bestowed on Cornelis Drebbel, a Dutch inventor who was invited to the court of King James I of England in 1604. 

Drebbel had already made a name for himself as an engineer and inventor, having created various contraptions in Holland, including perpetual motion machines, clocks, and a self-regulating furnace. But it was during his time in England that Drebbel came up with arguably his most famous invention. In 1620, while working for the Royal Navy, Drebbel designed and built the first documented navigable submarine. None of his original records or engineering drawings survive, but there were enough eyewitness accounts to give us a good idea of how his submarine worked. 

The basic design was like a rowing boat, but with raised and meeting sides, and the whole vessel covered in greased leather. It had a watertight hatch in the middle and was propelled by oars that came out the side through watertight leather seals. Large pigskin bladders were used to control diving and surfacing, while tubes floated at the surface of the water likely provided the crew with oxygen. 

Drebbel built three submarines in total, each one bigger than the last — the final model had six oars and could carry 16 passengers. He tested them on the River Thames in London in front of thousands of spectators, one of whom was King James I. Contemporary accounts suggest that the king himself may have joined Drebbel on one of his test runs, making James I the first monarch to ride in a submarine. Accounts of the test runs, which continued until 1624, state that the submarine could travel underwater from Westminster to Greenwich and back — a three-hour trip with the boat traveling 15 feet below the surface.

The Revolutionary War’s Turtle

Another hugely significant submarine journey took place a little more than a century and a half after Drebbel’s historic underwater excursions. In 1776, a one-man submersible called the Turtle became the world’s first combat submarine during the American Revolutionary War. 

Designed by American inventor David Bushnell, this remarkable vessel was shaped somewhat like a large acorn, or, as Bushnell described it in a letter to Thomas Jefferson, as “two upper tortoise shells of equal size, joined together.” The submarine was propelled vertically and horizontally by hand-cranked and pedal-powered propellers operated by the single pilot. 

On September 7, 1776, Sergeant Ezra Lee of the Continental Army piloted the Turtle in the first ever combat mission involving a submarine. He used the vessel in an attempted attack on the British flagship HMS Eagle in New York Harbor. The Turtle was equipped with a mine that was to be attached to the hull of the enemy ship, but Lee failed to attach the explosive charge to the hull. The perilous mission was a failure, as were subsequent missions involving the sub. It was, nevertheless, a pivotal moment in the history of warfare, with the Turtle demonstrating the potential of submarines in combat. 

 It Was Aesthetically Appealing as Well as Practical

While sepia toning was primarily adopted for its preservation benefits, its aesthetic qualities also contributed to its widespread appeal. The warm, brownish hues of sepia prints conveyed a sense of elegance and timelessness. Unlike the stark contrast of black-and-white images, sepia tones were considered more flattering, making them particularly popular for portraits and sentimental keepsakes. The process deepened contrast, refined tonal gradation, and offered a softer, dreamlike image compared to black-and-white photography.

Culturally, sepia-toned photographs came to define the late-Victorian and Edwardian eras, a period marked by industrial progress and significant social and cultural changes in both Europe and the United States. Photography during this time captured moments from everyday life, such as family portraits, weddings, christenings, and postmortem photos of deceased loved ones, as well as architecture, nature scenes, and historical events. As a result, sepia-toned photography became linked to collective memories of the past, reinforcing its association with history and nostalgia.

Sepia Toning Eventually Fell Out of Favor 

The dominance of sepia-toned photographs began to fade in the early 20th century as advancements in technology introduced more efficient and affordable ways to preserve images. Black-and-white photography became the standard because it was simpler, faster, and less costly than the additional chemical treatment required for sepia toning. By the 1920s and ’30s, photographers increasingly preferred gelatin silver prints, which produced high-quality black-and-white images without the need for sepia toning.

The decline of sepia toning continued with the rise of color photography in the mid-20th century. As color film became more widely available and affordable in the 1940s and ’50s, both sepia and black-and-white photography fell out of fashion. Sepia tones remained relevant in some artistic and archival contexts, but today that nostalgic aesthetic is often recreated digitally rather than through chemical processing.

Why QWERTY?

Here’s where things get a little foggy. An often-repeated explanation for the QWERTY keyboard layout is that it was designed by Sholes to slow typists down in order to prevent typewriters from jamming. If you’ve ever used an old-fashioned typewriter, you might have noticed how easy it is to strike letters in quick succession, or simultaneously, which can cause the type bars to become stuck together. 

But would Sholes really have sabotaged his own keyboard layout to hamper the speed of operators? In reality, there is little to no hard evidence of any deliberate slowdown. And the patent that first mentions the QWERTY layout contains no direct mention of why the keys were placed in such a manner. If it was indeed designed to cause fewer jams, this feature would likely have been a primary attribute of the patent. What’s more, at the time that Sholes patented the QWERTY layout, there were no “touch typists,” so no one was typing particularly quickly, let alone speed-typing. 

So, why did QWERTY become standard? One convincing and particularly thorough answer comes from Kyoto University researchers Koichi Yasuoka and Motoko Yasuoka. In their 2010 paper “On the Prehistory of QWERTY,” the researchers conclude that the mechanics of the typewriter did not influence the keyboard design. Instead, the QWERTY system was a rather circuitous result of how the first typewriters were being used. 

Among the most prominent early adopters of early typewriters were telegraph operators, whose priority was to quickly transcribe messages. These operators found an alphabetical keyboard arrangement to be confusing and inefficient for translating morse code. The Kyoto paper suggests the QWERTY keyboard evolved over several years as a direct result of the input provided by these telegraph operators. According to the researchers, “The keyboard arrangement was incidentally changed into QWERTY, first to receive telegraphs, then to thrash out a compromise between inventors and producers, and at last to evade old patents.”

In other words, QWERTY came about through a combination of factors. There was direct input from telegraph operators, as well as compromises made between inventors and producers — practical changes made by the manufacturers who actually had to mass produce the product. (The keyboard layout on Scholes’ original prototype, for example, was altered by the mechanics at Remington.) And then there were old patents to contend with. In 1886, a new company called Wyckoff, Seamans & Benedict (WS&B) released the Remington Standard Type-Writer No. 2. To avoid existing keyboard layout patents, the company slightly altered the design, placing M next to N and swapping around C and X. This became the QWERTY format keyboard we use today.

The Persistence of an Imperfect Design

While the precise intentions behind Sholes’ QWERTY design are at least partially lost to history, there is undoubtedly a strong argument against the popular belief that it was designed to slow typists down. 

What we know for sure is that the QWERTY layout is remarkable for its staying power. Despite the development of potentially more efficient keyboard layouts — most prominently the Dvorak layout, designed in the 1930s, which is supposed to be faster and more comfortable — QWERTY has remained the global standard. By the time alternative layouts were proposed, millions of people had already learned to type on QWERTY keyboards, and switching would have required massive retraining efforts for typists, not to mention a lot of grumbling from the general public. 

So, for now at least, QWERTY is very much here to stay — at least on laptops and PCs. Researchers at the University of St Andrews in Scotland have developed a split-screen keyboard they claim can increase typing speeds for touchscreen users who type with their thumbs. Known as KALQ (the letters at the bottom right of that keyboard), its layout is a radical departure from the QWERTY system, which has been unchanged for about a century and a half. Will KALQ gain a foothold? Only time, and more typing, will tell. 

Green Gemstones

The ancient Romans seemed to believe that emeralds and other green gemstones could be used as a means for soothing the eyes and possibly providing visual aid. One famous example appears in Pliny the Elder's Natural History, where the author notes how Emperor Nero watched a gladiatorial event with the assistance of a smaragdus — an emerald or similar gem. However, historians largely believe that the stone may not have magnified the spectacle so much as it helped to block the glare of the sun.

Water Globes

In his first volume of Naturales Quaestiones (Natural Questions), the Roman philosopher Seneca described the magnifying effect of water in glass: “Letters, however small and dim, are comparatively large and distinct when seen through a glass globe filled with water.” His contemporary Pliny the Elder also noted the lenslike qualities that resulted from combining these elements, although his observation was related to the potential for flammability when focusing the sun's rays through a glass water vessel. While the result may have been satisfactory, Seneca's lack of follow-up thoughts suggest that this particular method of magnification likely wasn't widely used.

Mirrors

In the same sentence describing the magnification qualities of the water vessels, Seneca wrote, "I have already said there are mirrors which increase every object they reflect." Indeed, concave metal, glass, or crystal mirrors could be used to magnify smaller texts for those with vision problems. As noted by Ilardi in Renaissance Vision From Spectacles to Telescopes, French author Jean de Meun wrote of the efficacy of this tool in the late-13th-century poem “Le Roman de la Rose,” although there aren’t many other documented uses of mirrors for this purpose.

Reading Stones

A major development in the area of visual tools came with the invention of reading stones. Often credited to ninth-century Andalusian scholar Abbas ibn Firnas, the concept of curved glass surfaces being used to magnify print was discussed at length in Arab mathematician Ibn al-Haytham's 1021 Book of Optics, which later received a wider audience with its translation to Latin.

Typically made from quartz, rock crystal, and especially beryl, reading stones were fashioned in a plano-convex shape, with the flat side against the page of a book and the rounded top providing a clear view of the lettering below. Initially used to assist the elderly with faltering vision, the stones became popular among younger readers as well, especially as beryl was said to possess magic and healing powers.

One surviving example of such reading stones are the 11th- to 12th-century Visby lenses discovered in Gotland, Sweden, in 1999. Along with providing excellent magnification of tiny text, many of these quartz lenses are mounted in silver, suggesting a decorative purpose as well.

It's unknown if the Visby lenses were the work of a local professional or somehow made their way from Muslim regions where other reading stones first appeared. Regardless, the quality of the images generated by these artifacts, and the craftsmanship that went into their creation, underscores how people were hardly left grasping in the dark for assistance in the days before eyeglasses became commonplace.

Glassmaking Is Thousands of Years Old

Ancient glass was made from three primary ingredients: sand (silicon dioxide or silica), an alkali oxide (typically soda ash or natron), and lime. When combined and heated to 2,400-2,700 degrees Fahrenheit, the ingredients fused to form glass. 

The earliest evidence of glassmaking includes objects such as beads, pendants, and inlays that were cast in open molds, but glass may have initially occurred as an accidental byproduct in the workshops of Bronze Age metalworkers and ceramicists. While archaeologists have found glass artifacts produced by the Egyptians and Phoenicians dating back to the second millennium BCE, current theory suggests that the first human-made glass dates back even further, to Mesopotamian craftsmen during the third millennium BCE, some 4,000 to 5,000 years ago.

The Birthplace of Glassmaking

Researchers have long debated the birthplace of glassmaking, in part because glass products, as well as the raw materials used for the glassmaking process, such as blocks of colored glass called ingots, were frequently exchanged along trade routes. But advances in archaeology and chemistry have helped researchers better pinpoint the origins of glassmaking to ancient Mesopotamia (modern-day Iraq). 

Situated between the Tigris and Euphrates rivers, Mesopotamia was well suited for trading its glass materials and glassmaking knowledge. By the second millennium BCE, artisans had developed sophisticated techniques to shape glass and create vessels. One such method, called core forming, involved creating a hollow vessel by covering a mud core with glass and then removing the hardened mud. Core-formed objects have been found in Mesopotamia, as well as Egypt, where glassmaking also flourished. 

Glass trading between Egypt and Assyria was mentioned in the Amarna Letters, a set of cuneiform clay tablets dating to the 14th century BCE that were excavated in the ancient desert city of Amarna, in modern-day Egypt. Not surprisingly, chemical analysis of glass excavated in Amarna found the glass was of Mesopotamian origin. Similarly, the presence of cobalt glass beads in Scandinavian Bronze Age tombs has provided evidence of a complex trading system linking Mesopotamia and Egypt with the Nordic Bronze Age cultures. These findings highlight the extensive trade networks of the ancient world, and demonstrate the far-reaching influence of Mesopotamian glassmaking, even as other cultures began to adapt and develop their own glassmaking methods.