Technology, World-Changing Inventions

Water Treatment Technology Through History

Water Treatment Technology Through History


Civilization has changed in uncountable ways over the course of human history, but one factor remains the same: the need for clean drinking water. Every significant ancient civilization was established near a water source, but the quality of the water from these sources was often suspect. Evidence shows that humankind has been working to clean up their water and water supplies since as early as 4000 BCE.

Cloudiness and particulate contamination were among the factors that drove humanity’s first water treatment efforts; unpleasant taste and foul odors were likely driving forces, as well. Written records show ancient peoples treating their water by filtering it through charcoal, boiling it, straining it, and through other basic means. Egyptians as far back as 1500 BCE used alum to remove suspended particles from drinking water.

By the 1700s CE, filtration of drinking water was a common practice, though the efficacy of this filtration is unknown. More effective slow sand filtration came into regular use throughout Europe during the early 1800s.

As the 19th century progressed, scientists found a link between drinking water contamination and outbreaks of disease. Drs. John Snow and Louis Pasteur made significant scientific finds in regards to the negative effects microbes in drinking water had on public health. Particulates in water were now seen to be not just aesthetic problems, but health risks as well.

Slow sand filtration continued to be the dominant form of water treatment into the early 1900s. in 1908, chlorine was first used as a disinfectant for drinking water in Jersey City, New Jersey. Elsewhere, other disinfectants like ozone were introduced.

The U.S. Public Health Service set federal regulations for drinking water quality starting in 1914, with expanded and revised standards being initiated in 1925, 1946, and 1962. The Safe Drinking Water Act was passed in 1974, and was quickly adopted by all fifty states.

Water treatment technology continues to evolve and improve, even as new contaminants and health hazards in our water present themselves in increasing numbers. Modern water treatment is a multi-step process that involves a combination of multiple technologies. These include, but are not limited to, filtration systems, coagulant (which form larger, easier-to-remove particles call “floc” from smaller particulates) and disinfectant chemicals, and industrial water softeners.

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Planned future articles on Sandy Historical will expand on some of the concepts mentioned here. Please visit this page again soon for links to further reading.

Historical Science & Technology

Minting Ancient Coins

No matter how many times the government proposes phasing out the penny, Ol’ Copper Lincoln and his jangly metal friends aren’t going anywhere anytime soon. Coins as currency are a tradition that dates back thousands of years. Today, coins used as currency are produced mechanically and automatically. Modern technology has turned coins into run-of-the-mill metal stampings—perfectly repeatable thousands and thousands of times, with little to no effort on the part of the machine operators. However, producing coins was once a far more involved process.

Stop: Hammer Time

Legitimate question: How did the first blacksmith make a hammer with which to blacksmith?

Since the dawn of the metal age, around 2000 BCE or so, blacksmiths have been hammering anvils to produce metal artefacts for countless uses. This means, of course, that blacksmiths were also the first minters of coins.

Minting coins is a far different beast than making a plow blade, however. Ancient blacksmiths had to do far more than just beat the metal into shape. Any joker with a hammer and a forge can turn out a round, flat piece of metal—these guys had to get more creative.

Drachma coin from the reign of Vologases VI (ca. 200 CE)

Drachma coin from the reign of Vologases VI (ca. 200 CE)

To that end, old-school minters used a variety of hand tools to stamp silver, gold, bronze, and other precious metals and alloys into coins. As precious metals tend to be relatively soft and malleable, iron dies, punches, molds, and other assorted tools were ideal for creating the decorative forms that adorn the front and back of early coins.

The earliest known coins were produced by Lydian blacksmiths in Asia Minor, starting around the 7th century BCE. Using a combination of molding (i.e. pouring molten metal—in this case, electrum, an alloy of gold and silver—into a mold the size/shape of the final coin) and hammer with tools and dies, the Lydians developed a method of coining that lasted centuries.

Adventures in Coin Minting

Round about the 16th century CE, the population and economy of Europe had both grown so much that currency coins were in high demand. This, in turn, meant that new and more efficient techniques of minting were necessary. Blacksmiths began to hammer metal into thin sheets that could easily be cut with shears to produce blanks. These blanks were then “coined” via hammer, anvil, and two-piece dies that formed the front and back of the coin simultaneously.

Wine and/or olive presses were also used for coin minting. Instead of crushing grapes or olives, the press was retrofit with coining dies and used to impress the desired image onto a coin blank. By modifying these devices further, ancient blacksmiths could produce multiple coins in a single process. This may well have been the first practical example of repeatable, mechanical metal stamping.

Despite these improvements and innovations, coin minting was far from perfect. Many surviving examples of ancient coins have off-center stamping or double-struck images that show the human element at work.

Photo credit: dynamosquito / Foter / CC BY-SA


A Brief History of Micro Molding

Micro molding, as the name suggests, is plastic injection molding process on the micro scale. Micro molded parts can be so miniscule that they must be inspected under a microscope—the high powered electron kind. In fact, it’s possible to make micro molded plastic parts so small that several of them can be assembled into a completed device, and that device is still small enough to be injected into medical patients via syringe—the normal, not freakishly huge and scary kind. How did this this unique, highly specialized process become a thing?

This tiny chess pieces were created via micro molding.

This tiny, detailed chess pieces were created via micro molding.

Descendant of Polyester

The first plastic material capable of being injection molded was polyester. Developed by Swedish chemist Jöns Jacob Berzelius in 1847, polyester was the first “condensation polymer” (a term also invented by Berzelius). Fifteen years later, British metallurgist and inventor Alexander Parkes created the first commercially viable manmade plastic, the cleverly named Parkesine. Though it could be heated and molded, and retained its molded shape when cooled, it was expensive to produce and was often physically unstable at best.

Improving on Parkesine, American inventor John Wesley Hyatt (lots of Jons/Johns in plastic molding history, eh?) developed celluloid, which retained the previous material’s moldability while eliminating its tendency to burst into flames while being heated. In 1872, Hyatt and his brother Isaiah patented the first injection molding machine. Though far simpler than modern automated, computer-operated injection molding machines, the Hyatt Bros.’ device operated on the same general principles at work in the process today. Some things just can’t be improved upon.

The process was further refined and improved upon for decades, but injection molding didn’t find wide use until the end of World War II, which created a huge demand for inexpensive, mass-produced products. American inventor James Watson Hendry is responsible for a great deal of innovation in 20th century plastic injection molding, having developed the first screw injection machine (1946) and the first gas-assisted injection molding processes (1970s).

From there, as technologies—particularly those in the medical and electronics industries—advanced, devices became simultaneously smaller and more powerful, the need for “micro” manufacturing grew. In the 1980s, the predecessor to micro molding technology was invented at the Karlsruhe Institute of Technology in Germany. Oh, those wacky Germans!

Photo credit: Jerry Bowley / Foter / CC BY-NC-SA

The Science of Film, Music & Art

The Zoetrope: Moving Pictures from ACTUAL Moving Pictures

Prior to the invention of motion pictures (or “movies,” as you lazy kids today call ‘em), mankind made several attempts to reproduce motion from still images. One of the earliest and most successful of these was the zoetrope, a device whose origins may date as far back as the 1st century BCE.


Fake It ‘til You Make It

The first and most common form of zoetrope, generally referred to as simply a “zoetrope”, is technically a “cylindrical zoetrope”. These devices consist of a rotating cylinder with vertical slits in its sides. A band of sequenced images is painted (or otherwise applied) to the inner diameter of the cylinder. As the cylinder rotates, users see these images passing by rapidly, and their sequencing and speed, along with the human eye’s “persistence of vision”, combine to create the illusion of movement. The slits, separated by sections of cylinder wall, keep the images from blurring together.

The earliest records of this invention date back to around 100 BCE, when a Chinese inventor name Ding Huan reported created a “variety of zoetrope” that could produce the illusion of moving pictures. There is no hard evidence of the existence of this device, however, and it is likely apocryphal.

The first cylindrical zoetrope for which legit evidence does exist is credited to William George Horner, a British mathematician. Horner’s invention, which he called a “daedaleum”, was based on the then-recently invented phenakistoscope disc, which performed a similar function in a similar matter. Invented in the early 1830s, Horner’s zoetrope place the viewing slits between the individual pictures.

It was not until the 1860s that the zoetrope’s popularity truly skyrocketed, however. A slight variation in Horner’s design placed the view slits above the pictures, and therefore made it possible to change out the still images within, thus creating new viewing experiences as the user so pleased. American inventor William F. Lincoln dubbed his version of the device the “zoetrope”, from the Greek for “wheel of life”, and the name stuck.

The zoetrope was an improvement on phenakistoscope discs, on which images were aligned radially around a disc’s diameter. The zoetrope allowed multiple people to view the moving images at the same time. No matter where they stood in relation to the device, every viewer would see the same thing.

The zoetrope was eventually displaced by the praxinoscope, which used mirrors and essentially the same principle to produce smoother images. The praxinoscope, too, was rendered obsolete by further technological innovations, such as the aforementioned motion pictures.

Subway Zoetropes

The illusion of movement created by a zoetrope works with linear motion, as well. To that end, artists and advertisers often create “linear zoetropes” along the walls of subway tunnels, using the movement of the train in place of a spinning cylinder to fool the viewer’s eye.

Created in 1980 (and restored in 2008), filmmaker Bill Brand’s “Masstransiscope” was the first subway zoetrope. Installed at a now-unused subway platform in New York City, the huge artwork consists of 228 hand-painted panels. As subway riders pass by, the movement of the train—along with strategically placed, slitted panels—makes the images appear to be in motion.

In September 2001, graduate student Joshua Spodek developed a linear zoetrope “advertisement” that was installed in the Atlanta subway system. This marked the first commercial use of a zoetrope in more than a century. The internally lit, nigh 1000-foot long display produces animation lasting nearly 20 seconds. Following its success, Spodek’s design was recreated in a number of subway systems throughout the world.

In the mid-2000s, both the Washington (D.C.) Metro and San Francisco Bay Area Rapid Transit (BART) system installed zoetrope advertisements. Subway zoetrope advertisements have also been installed, with varying levels of success, in Kiev, Ukraine, Mexico City, and various locations across Europe and Asia.

Video credit: Chris Artell
Photo credit: Foter / CC BY-SA

Historical Science & Technology

“Philosophical Transactions of the Royal Society”

Philosophical Transactions of the Royal Society, or—for the sake of brevity and my poor lil’ typing fingers—PTRS, is a scientific journal published by (surprise, surprise) the Royal Society. It was first published in 1665, making it the world’s first journal devoted exclusively to science, and is still in print today.


The first issue of PTRS was published March 6, 1665, and bore the unwieldy full title of Philosophical Transactions, Giving Some Account of the Present Undertakings, Studies, and Labours of the Ingenious in Many Considerable Parts of the World. Say that five times fast!

Edited and published by Henry Oldenburg, the first secretary of the Royal Society, at his own expense, PTRS introduced the now-familiar trappings of the scientific journal: registration (date stamping/provenance), certification/peer review, dissemination, and archiving. These ideas were sketched out prior to publication in a series of letters between Oldenburg and Robert Boyle.

Henry "Hank the Tank" Oldenburg

Henry “Hank the Tank” Oldenburg

In exchange for funding PTRS, Oldenburg was allowed to keep the profits from sales of the publication, which initially proved to be very little—just enough to cover Oldenburg’s rent. Additionally, the journal served as a labor-saving device for Oldenburg, as it replaced much of his letter-writing correspondence on scientific matters.

Articles in Issue #1 of Philosophical Transactions of the Royal Society included the first published report on Jupiter’s Great Red Spot, notes for the improvement of optic glasses, a review of Boyle’s Experimental History of Cold, and “A Narrative Concerning the Successes of Pendulum-Watches at Sea for the Longitudes”, among others.

18th & 19th Centuries

By the mid-18th century CE, numerous other notables had served as editor of the PTRS, including Hans Sloane and Cromwell Mortimer. As before, the cost of publishing and distributing journal fell to its editor. In 1752, the Royal Society itself took over the paper, noting that henceforth it would be published “for the sole use of this Society.”

The costs associated with producing the PTRS were paid for by members’ subscriptions. The journal was a money pit, at the time costing twice as much to publish as it brought in in revenue. Fully two-fifths of the PTRS’ distributed copies were given away for free; back issues sold slowly but steadily.

Editorial duties were covered by the Royal Society’s Committee of Papers, who chose what to publish or not publish based almost solely on 300- to 500-word abstracts of the submitted works read during weekly committee meetings. The President and Secretaries of the Royal Society sometimes bypassed this selection process to promote works they liked or block those they didn’t. The latter practice was, unsurprisingly, frowned upon by the writers of said pieces, and an attempt to unseat then-Society President Joseph Banks is widely attributed to several begrudging authors.

By the mid-1850s, publication of the PTRS had come to strain the Royal Society’s finances. Its sales now brought in less than a quarter of the publication costs. To combat this, Treasurer Edward Sabine suggested a restriction on the length and number of pieces published in the journal. It was not until 1877, however, that the Royal Society finally switched to a larger and less expensive printing house to produce the paper.

At roughly the same time, the submission and approval process was made more formal. While committee members had previously brought articles before the committee themselves, authors now had to submit their own works to the Committee of Papers. Publishing approval was made more involved, with several “referees” making final, formal comments for or against works prior to their final selection or rejection.

20th Century & Beyond

By the start of the 20th century CE, The Philosophical Transactions of the Royal Society has established strict rules for format and style; any submitted work not meeting these standards was summarily dismissed.

The actual cost of printing an article in the journal was also made part of the committee’s selection process—i.e., shorter articles, which used less paper and ink and therefore “cost” less to publish, became favored over longer pieces. Authors were often asked to reduce the number of illustrations or tables in their piece, or to edit them for length, in order to secure inclusion.

It was not until 1948 that revenues from the PTRS finally began to outweigh the publishing costs. Improved (and therefore less expensive) printing technology and a significant number of new subscribers combined to bring the journal into the black for the first time.


Today, the Royal Society and the PTRS still exist. A dedicated selection committee and professional editors now oversee its publication. The Philosophical Transactions of the Royal Society is now published digitally, and is read by scientifically-minded folks all around the world.

Photo credit: Foter / Public Domain Mark 1.0


Drawing Deep

Have you ever washed dishes in a metal sink, used a riding lawnmower, or fueled up a motorcycle? If so, you’ve come face to face with something called a “deep drawn shell.” A sheet of metal is carefully stretched, bent, and otherwise formed into a distinct shape—such as a sink, lawnmower deck, or gas tank. Metal doesn’t just come out of the ground in those shapes, and the machines used to shape the metal didn’t hatch out of eggs, so how did we get here?

The Waterbury Manvilles

In the late 19th Century CE, Eli Manville, a talented mechanical engineer from Waterbury, Connecticut, began working on new methods of producing shaped metal parts. Along with his brother Frank, Manville founded the Eli Manville Company, and the brothers combined their technical expertise to invent a number of new devices and processes that would become integral to America’s nascent industrial boom. Early machines produced by the Manvilles include the Four Slide and the Hendey Planer and Shaper.

As gas-powered lighting was becoming more and more common at the time, brass components for light fixtures were in increasingly high demand. To meet this market need, the Eli Manville Company got into the brass fabrication game, and developed a number of specialized methods for producing brass tubes, brass lamps, and other brass products.

Well gas my brass!

Well gas my brass!

Later, in 1880, the Manville Company started manufacturing brass eyelets, the type used in boots, canvases, corsets, and the like. It soon became clear to Eli Manville that the equipment his company used to produce these eyelets was inadequate, too slow, too difficult to use, and too expensive to make continued eyelet production feasible. To rectify the problems with his existing machinery, Manville developed what is widely believed to be the world’s first transfer press.

Manville’s transfer press was wildly successful, and paved the way for the production of more complex drawn metal parts. Before long, new tooling and materials were being used with the eyelet machine to create a wide range of products. Production speeds increased dramatically, as did the quality and accuracy of the parts coming out of the machine.

Ongoing Technological Improvements (Naturally)

As with every invention that proves useful, Manville’s eyelet machine soon evolved into a more all-purpose metal drawing system. Over the years, numerous new technologies have been added to Manville’s original design to develop the high tech, high precision machines used to create drawn metal parts today.

Hydraulic-powered mechanisms, computer software, automated controls, and other advancements make it possible for these machines—which still operate on the same general principles of material formability—to produce the complex drawn shells and other intricate drawn metal parts used by modern manufacturers.

Photo credit: andy castro / Foter / CC BY-NC