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.

The Science of Film, Music & Art

The Legend of the Man of Pac

Pac-Man was first released in the United States in October 1980, by Midway Games. The game has been incredibly popular since its debut, and considered a video game classic. If you don’t know Pac-Man, or have never played the game…how is that even possible? Google “play Pac-Man”, play a few rounds, and thank me later. We’ll be here when you’re done.

Birth of the Pac

At the time of Pac-Man’s release, the most popular arcade games were so-called “space shooters” such as Asteroids and Space Invaders. Pac-Man was then unique, and created an entirely new genre (the “maze chase game”), as well as spawning one of the most successful franchises in the video game history.

Pac-Man was developed almost entirely by Toru Iwatani, a young employee of Namco, the game’s original Japanese publisher. Based on the concept of eating, the game’s Japanese title is Pakkuman, meant to mimic the sound of ferocious masticating. (“Paku-paku” is the Japanese equivalent of “nom nom nom”.) According to Iwatani, the idea of power pellets that allow Pac-Man to eat and defeat his enemies was inspired by Popeye’s spinach-powered muscles.

The simple design of the Pac-Man character—essentially a circle with a small, triangular wedge missing—was based on a simplified, stylized version of the Japanese character for mouth, kuchi (口). In the early days of the game’s success, Iwatani said the shape was inspired by a pizza missing a slice, likely in an effort to appeal to the literal appetites of the world’s hip, pizza-partying youth.

Iwatani intentionally designed elements of Pac-Man to appeal to as broad an audience as possible. The main demographic for arcade video games at the time was young boys and teenagers, so Iwatani added the game’s now-familiar and much-imitated maze structure and cutesy ghost “enemies” to appeal to female players.

A Japanese "Puckman" arcade cabinet.

A Japanese “Puckman” arcade cabinet.

Four months after its release in Japan, Pakkuman was picked up by Bally through their Midway Games division. In reference to the character’s hockey puck-like shape, and as a nod to the game’s original moniker, Iwatani suggested calling the game Puck Man. Midway changed it to Pac-Man to eliminate the rather obvious vandalism opportunity of changing the “P” to an “F”. Additionally, the cabinet artwork was changed, and the speed and difficulty of the game were increased.

Legacy of the Pac

Pakkuman was not initially a major success in Japan, as those pesky space shooters remained immensely popular. Upon its arrival in North America as Pac-Man, however, the game was massively successful, to the surprise of most in the industry. The game became far more popular than any other arcade game in history, and grossed over $1 billion—literally in quarters—by the end of the decade.

Pac-Man had sold more than 400,000 arcade cabinets worldwide by 1982, and an estimated 30+ million individual players had played the game. That same year, revenues from Pac-Man licensed products—both official and unofficial—totaled over $1 billion dollars, not adjusted for inflation. Today, Pac-Man is far and away the highest-grossing video game of all time, with a total gross (again, in quarters) in excess of $2.5 billion dollars.

It is considered one of the most influential video games of all time, in any genre and any era. Pac-Man himself became one of the first, and remains one of the most recognizable, video game mascots; Pac-Man singlehandedly established the maze chase genre. The game opened up gaming to a female audience. It was the first video game to feature power-ups (the aforementioned power pellets). Pac-Man is included in both the Smithsonian Institution in Washington, D.C., and the Museum of Modern Art in New York, New York.

Photo credit: kazamatsuri / Foter / CC BY-ND

Historical Science & Technology

The Piri Reis Map of 1513

The Piri Reis map, named for its creator, Ottoman-Turkish admiral, geographer, and cartographer Piri Reis, is an ancient world map created circa 1513. Roughly one-third of the map survives today. The surviving portion depicts the western coasts of Europe and North Africa, as well as the eastern coast of Brazil; the Canary and Azores Islands in the Atlantic Ocean are shown, along with what seems to be Japan and the mythical isle of Antillia.

The Map Itself


The Piri Reis map is drawn on gazelle skin parchment. The surviving portion of the map details the western coast of Africa and the eastern coast of South America. It is noted for its remarkable accuracy (considering the era in which it was made). piri reis map

It is claimed that Piri Reis used Christopher Columbus’ maps—which are otherwise lost—as a source for his maps, along with extensive knowledge of additional exploration of the New World. The map’s legend states that it was based on about 20 other charts and medieval European world maps, including ten Arab maps, eight Ptolemaic maps, and four Indian maps of Portuguese origin.

The map is drawn as a portolan chart, a navigational map based on compass directions and estimated distances observed by sailors while at sea. Some early modern analyses of the map suggested it was an azimuthal equidistant projection centered on Cairo, Egypt, but further study has shown that it points to the intersection of what are now known as the prime meridian and the equator.

A Brief History

Signed by Reis and dated in the Islamic year 919 AH (1513 CE), it was gifted to the Ottoman Sultan Selim I in 1517. From there, it’s history is either unremarkable or unknown until 1929, when it was rediscovered by German theologian Gustav Adolf Deissmann.

Diessmann had been commissioned by the Turkish Ministry of Education to catalog the non-Islamic items of the Topkapi Palace library. The map was discovered amongst a bundle of disregarded materials. Suspecting its significance, Deissmann showed the map to renowned orientalist Paul Kahle, who identified it as Reis’ work.

The rediscovery of the Piri Reis map was major worldwide news. At the time, it was the only known example of one of Columbus’ world maps—geographers had been searching for centuries for a “lost map of Columbus” that he had supposedly drawn while in the West Indies. It was also the only 16th century map that showed South America in its correct longitudinal position.

Today, the Piri Reis map is kept where it was first rediscovered, in the Library of the Topkapi Palace in Istanbul (not Constantinople), Turkey. It is not on public display.

Photo credit: Piri Reis / Foter / Public Domain Mark 1.0

Historical Science & Technology, Technology

EDM Sans Skrillex

Long before Corey Feldman’s doppelganger started dropping sick beats, there was another, much more useful and pleasant-sounding EDM: electrical discharge machining. Sometimes known as “spark machining”, “die sinking”, “wire erosion”, and “what?”, EDM is a unique manufacturing process that, as the official name suggests, uses electrical discharge to cut the desired part shape from metal materials.

A Brief Explanation of the EDM Process

In electrical discharge machining, material is removed from the workpiece (the “raw” material) by a series of fast, nearly-constant electrical current discharges between two electrodes, both of which are sunk in a dielectric liquid and goosed with electric voltage. The first electrode, called the tool-electrode, moves across the workpiece, as needed, to make the necessary cuts; the second electrode, called the workpiece-electrode, is just the workpiece itself—it pretty much just sits there.



There are two basic types of electrical discharge machining, sinker EDM and wire EDM, both of which operate on the same general principals.

Sinker EDM generally uses oil as the dielectric fluid. As the tool approaches the workpiece, the fluid breaks down, creating a plasma channel through which sparks jump. Sparks strike the workpiece one at a time, hundreds of thousands of times per second. Microsecond control of spark time (length) allows for cleaner or rougher cuts, as the part(s) being made require. Sinker EDM is used to create complex, 3D part shapes.

Wire EDM uses a thin, single strand of electrified wire (often brass) to cut through the workpiece like a cheese slicer (kind of). To prevent the ongoing electrical erosion from breaking the wire, it’s constantly fed from a spool through upper and lower CNC-controlled guides that maneuver the electrified wire through the material to cut the desired part shape. Wire EDM can cut intricate or delicate shapes in metal plate as thick as 30 cm. Deionized water is the most common dielectric fluid for wire EDM.

A Brief History of EDM

Joseph Priestly, an 18th century English physicist with the most 18th-century-English-physicist-sounding name ever, was the first to realize the erosive effect of electrical discharges of metal materials. It was not until the early 1940s, however, that the EDM process was refined for use in manufacturing. The Lazarenko brothers, noted Russian scientists, somewhat accidentally invented an early EDM system. Whilst working on a different project, they discovered that the erosive effects of electrical sparks are much more effective and easy to control when the electrode and workpiece are submerged in dielectric liquid. Their first EDM machine, created to machine difficult materials like tungsten, utilized an RC circuit to charge the electrodes. Hence, it was known as an RC-machine at the time.

At roughly the same time, a team of American scientists developed a rudimentary EDM machine to help remove broken drills and tapes from aluminum castings. As they refined their first designs, they added automatic spark repetition capabilities via an electromagnetic interrupter that could produce 60 carefully controlled sparks per second. This was further refined in later iterations, using vacuum tube circuits to increase the output to thousands of sparks per second. The more plentiful and more consistent the sparks, they found, the cleaner the cut.

Wire EDM machines were developed in the 1960s, and the earliest (pre-CNC, mechanical-“computer” operated) NC machines were built on modified punched-tape milling machines. Once again, the Russkies were the first to develop a commercially viable version, debuting a wire EDM system in the USSR in 1967. The first true CNC-controlled wire EDM machine was produced by the Andrew Engineering Company in 1976, based on R&D by a group led by American scientist David H. Dulebohn.

Photo credit: ericskiff / Foter / CC BY-SA

Historical Science & Technology

The Bone Wars

Also known as “the Great Dinosaur Rush,” the Bone Wars took place during a time of intense speculation about and significant discoveries of fossils in North America. The “wars” themselves were waged by rival paleontologists Edward Drinker Cope and Othniel Charles Marsh. The competition between Cope and Marsh was far from a friendly one: both used underhanded methods, including bribery, theft, and the destruction of bones, in attempts to outdo each other. It did not end particularly well for either man.

Not Quite A Gentleman; Not Quite A Professional

Early on in their careers, Cope and Marsh were rather close. They worked together on several occasions, and even named newly-discovered species for each other. However, both men had strong personalities, and they came from very different backgrounds and schools of scientific thought.

The argumentative, hot tempered Cope, from a wealthy and influential Quaker family, was a staunch supporter of Neo-Lamarckism. Meanwhile, the more methodical and introverted Marsh, born into a poor family in Lockport, New York, backed Charles Darwin’s theory of evolution by natural selection. A cohort of the two remarked, “The patrician [Cope] may have considered Marsh not quite a gentleman. The academic [Marsh] probably regarded Cope as not quite a professional.”

Following a fossil-finding excursion to Cope’s family’s marl pits in New Jersey, Marsh covertly bribed the pit operators to send news of future fossil finds to him, rather than Cope. From there, personal relations between the duo fell apart quickly. The men attacked each other in newspapers and scientific publications, each hoping to ruin his rivals’ reputation and scare off future financial backers.

Dueling Dino Diggers

In 1872, Cope set off on an expedition into the American West to find new fossils. After being left high and dry in Fort Bridger, Wyoming, by his supposed supporter, the geologist Ferdinand Hayden, Cope put together a team at his own expense. Two of the men in Cope’s new crew were also employed by Marsh, and one of them accidentally forwarded some of Marsh’s material to Cope instead. Cope sent the materials back to Marsh, but Marsh was furious at having his men poached by his rival. (One claimed he had joined Cope only so he could steer him in the wrong direction.)

The growing hostilities between the two paleontologists came into the open in the spring of 1873. Marsh and Cope had each made a number of significant discoveries of ancient reptile and mammal fossils in Western bone beds. In several instances, their discoveries overlapped each other, and they openly battled and bickered over classifications and nomenclature. Ultimately, it was determined that most of Marsh’s proposed names were valid; none of Cope’s were.

Later that year, both men set in motion new expeditions to what is now South Dakota. Marsh, with scads of bones awaiting study and cataloging, stayed home, but enlisted the services of numerous local collectors who would do the actual digging and discovery for him before sending the bones back to his offices at Yale University. Cope, meanwhile, worked with the Army Corp of Engineers, and later struck up a deal with Chief Red Cloud to collect fossils on the Oglala Sioux’s tribal lands.

Apotosaurus skeleton at the Peabody Museum of Natural History at Yale University, once curated by Othniel Marsh.

Apotosaurus skeleton at the Peabody Museum of Natural History at Yale University, once curated by Othniel Marsh.

Rough Stuff at Como Bluff

An 1877 letter from Arthur Lakes, of Golden, Colorado, to Marsh told of Lakes’ discovery of massive bones in the nearby mountains. Lakes also sent a collection of the colossal bones to Marsh’s office. Marsh was slow to respond, so Lakes send another letter and accompanying shipment of bones, this one to Cope. However, Marsh was able to secure the prospector’s services, and published a description of the find in the American Journal of Science. Cope was preparing his own interpretation, but found that his bone supply had dried up—Lakes would be sending all further shipments to Marsh alone.

Shortly thereafter, Cope received another letter, this one from naturalist O.W. Lucas. Lucas had discovered an array of fossilized bones near Cañon City, Colorado. Hoping to cut Cope off at the pass, Marsh instructed two of his associates to set up a quarry nearby on his behalf. However, Lucas was already working with Cope and refused to jump ship to Marsh’s team.

A short while later, Marsh was contacted by two Union Pacific workers who were helping build the Transcontinental Railroad. The men, known as Carlin and Reed, claimed to have found numerous fossils near Como Bluff, and noted that others in the area were “looking for such things.” Marsh rightly assumed this meant Cope.

Fearing a Lakes repeat, Marsh quickly sent money to Carlin and Reed to secure their services and their silence. Marsh and Carlin soon met face to face, and came to terms wherein Carlin and Reed would be paid a monthly fee for their services, in addition to possible bonuses if their findings proved to be especially important. Carlin and Reed were ultimately dissatisfied with the agreement, feeling that Marsh, who flatly refused to negotiate the conditions of the deal, had bullied them into it.

Como Bluff proved to be a veritable treasure trove of fossils, with train cars full of bones being shipped to Marsh’s Yale offices on a steady basis. Dinosaur all-stars such as Stegosaurus and Apatosaurus were discovered and named based on the Como Bluff findings.

Carlin and Reed, seeing the potential for bigger paychecks, started spreading the word on the Como Bluff area. Soon, Cope had sent “dinosaur rustlers” to the region in an attempt to steal fossils from Marsh’s team. By the winter of 1878, Carlin had left Marsh’s employ and joined up with Cope.

Over the next fifteen years, from 1877 to 1892, Cope and Marsh personally funded numerous expeditions to Como Bluff which yielded literally tons of fossils. Both teams were hit hard, and repeatedly, by the weather, and even harder by sabotage from the opposition.

Both men sent spies into the other’s camps. Tensions grew within excavation teams. Marsh and Cope both ordered their workers to destroy any remaining bones at cleared-out quarries to prevent them from falling into their rival’s hands, and many sites were filled in with dirt and rocks to keep the competition at bay.

The War Draws to A Close

By 1884, Marsh was pulling ahead to victory in the Bone Wars. Thanks to rich and powerful contacts in Washington, D.C., he was made the head of the government’s consolidated geological survey team. Cope, meanwhile, faced numerous setbacks and soon found himself with his fossil collection as his only significant asset.

Cope soon got the chance to turn the tables on his former colleague. He spoke to disgruntled workers who had been dismissed from Marsh’s survey team, and with the help of his friends Henry Osborn, a Princeton professor, and William Hosea Ballou, a “newspaper man from New York,” published a series of articles journaling the mistakes and misdeeds Marsh had committed as leader of the survey.

In the articles, Cope lobbied charges of plagiarism and financial mismanagement against Marsh. Marsh published a rebuttal, and other, unaffiliated newspapers joined the fray with pieces speaking out against each man. Though the pieces gained nationwide attention, neither side gained much traction, and no clear “winner” ever emerged from the widely-published spat.

The rivalry between Cope and Marsh kept going strong, at least on a personal level, until Cope’s death in 1897. By that time, both men were destitute and each had had to sell significant portions of their respective fossil collections to support themselves.

Cope did strike a final blow, however. Upon his death, he had his skull donated to the University of Pennsylvania so that his brain size could be measured, in the hopes that it would prove to be larger than Marsh’s. (At the time, brain size was thought to be an accurate measure for intelligence.) Marsh never answered the challenge, and was buried in one piece two years later.

Photo credit: rynoceras / Foter / CC BY-NC-ND

Historical Science & Technology, World-Changing Inventions

Magna Rola: The Treadwheel Crane

Ever wondered how Roman cathedrals or Medieval castles were built? For example, how’d they get those huge stones way up to the top? A few different methods were used, but the most common solution was the treadwheel crane, a wooden, human-powered lifting and lowering machine.

A Hard-Working Hamster Wheel

In simplest terms, the treadwheel crane was a large wooden wheel that turned around a central shaft. The wheel enclosed a treadway wide enough for two workers to walk side by side. A rope running through a pulley at the end of the crane’s lifting arm is turned onto a spindle by the wheel’s rotation. This rotation lengthens or shortens the rope, allowing the crane to lift or lower its load.

Unlike modern cranes, the treadwheel crane was only capable of moving its load vertically. There was little to no allowance for lateral movement. As such, additional workers were required to guide the load to its final position. Stones and stone blocks were generally lifted via slings, while smaller items would be loaded onto pallets or into barrels or baskets prior to lifting.

Interestingly, medieval treadwheel cranes rarely included ratcheting or braking mechanisms to prevent runaways or backsliding. Such features were rendered unnecessary by the high friction force exercised on the machines, which naturally prevented such occurrences.

Treadwheel cranes were usually placed within the building they were being used to construct. When one level was completed, and the floor above was secured and stable, the crane would be disassembled, moved up to the next level, and reassembled to continue the building process. Because of this, many of the ancient treadwheel cranes still in existence are found at the top of castle or church towers, above the vaulting and below the roof.

60X More Efficient than the Egyptians

The most well-known treadwheel crane, the one about which the most contemporaneous writing survives, is the Roman Polyspastos. With just two men walking on its treadway, it was capable of lifting up to 6000 kilograms (3000 kg per person). In contrast, when building the pyramids, the ancient Egyptians used ramps that required roughly 50 men to move a 2.5 ton block—about 50 kg per person. If you math it out, you’ll find that the treadwheel crane is 60 times more efficient. (Perhaps unsurprisingly, as ramps are notoriously inefficient.)

Surviving 17th century treadwheel crane in Harwich, Essex, England.  (see below)

Surviving 17th century treadwheel crane in Harwich, Essex, England.
(see below)

After the fall of the Roman Empire, the treadwheel crane fell out of common use for several centuries. It was reintroduced in the High Middle Ages; the oldest recorded mention of a Medieval-era treadwheel crane comes from a French manuscript dated to 1240 CE.

Used throughout France, England, the Netherlands, Belgium, and Germany, treadwheel cranes were used in the construction of the lofty Gothic cathedrals of the era. The technology was also frequently used in harbors to load and unload ships, and in mining to excavate dirt and rocks, as well as loads of valuable minerals, from mine shafts.


Original, historical treadwheel cranes are now somewhat difficult to find. Two examples can be found in the United Kingdom, one in Guildford, Surrey, and the other in Harwich, Essex. Both date back to the 17th century CE. The Guildford crane was last used in 1960 to help build the Guildford Cathedral. Both cranes are now protected as part of the UK’s Statutory List of Buildings of Special Architectural or Historic Interest.

Photo credit: diamond geezer / Foter / CC BY-NC-ND