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

The Einstein Refrigerator

Did you know that Albert Einstein invented a new type of refrigerator in 1926? It’s true! (We wouldn’t be writing about it otherwise. Are you calling us liars?!) Einstein invented his fancy fridge jointly with his former student Leó Szilárd, and received a US patent for the device on 11 November 1930. So, what’s so cool about the Einstein Refrigerator?

Classical Gas

The Einstein Refrigerator is a type of absorption refrigerator—that is, one that uses a heat source to provide the energy that drives the cooling process. A true paradox, that. Based on an earlier design by crafty Swedes Baltzar von Platen and Carl Munters, Einstein and Szilárd’s creation had no moving parts and was designed to operate at a constant pressure.

The duo were inspired to develop their design after reading newspaper reports about a family in Berlin who were killed by toxic fumes emitted by their refrigerator when one of its seals failed. They designed their refrigerator with no moving parts specifically to eliminate the potential for seal failure. Einstein and Szilárd explored a wide range of practical applications for a variety of cooling cycles, leading to the development of multiple models.

Einstein, having worked in the Swiss Patent Office, applied for numerous patents (in several countries) for their invention. The general historical consensus is that Szilárd did most of the actual inventing; apart from acting as a consultant on the project, patent applications were more or less the extent of Einstein’s involvement in his namesake refrigerator’s invention.

Big Al Einstein in his patent slingin' days.

Big Al Einstein in his patent slingin’ days.

Unlike Thomas Edison, however, Einstein did not swoop in to take all the credit while leaving his cohort to historical anonymity; nor did he have Szilárd murdered. Ultimately, he and Szilárd were awarded 45 joint patents for three different refrigerator models. A number of these patents were subsequently bought up by Swedish refrigerator manufacturer Electrolux, though no commercial models based on the Einstein-Szilárd were ever built.

Modern Gas

Despite Einstein and Szilárd’s best efforts, gas refrigerators are more or less extinct today, due to the potential for carbon dioxide poisoning. However, Oxford University researchers recently began work on a project to develop refrigerators and other appliances that can be used in areas with no electricity. An updated gas refrigerator prototype has been completed; the Oxford team speculates that further design improvements and changing the type of gas used could quadruple the device’s efficiency.

Photo credit: huanjo via / CC BY-SA

Historical Science & Technology, Important People, Important Discoveries

Big Nick Steno & the Rise of Stratigraphy

Stratigraphy is a branch of geology that specifically studies rock layers and layering (strata and stratification, respectively). First established in the late 17th Century CE by Nicolas Steno, stratigraphy is of primary concern in the study of sedimentary rock and layered volcanic rock.

Steno’s 4 Defining Principles

Born in Copenhagen on New Year’s Day 1638, Nicolas Steno was a Danish scientist and, later, a theologian and Catholic bishop. (This last bit lead to his far-later beatification by Pope John Paul II, in 1988.) The son of a goldsmith whose work was regularly commissioned by King Christian IV of Denmark, Steno began studying medicine at the University of Copenhagen at age 19.

After completing his studies, he travelled throughout Europe—with notable stops in the Netherlands, France, Germany, and Italy—to meet with and learn from prominent doctors and scientists. These fellow scholars inspired Steno to make important scientific discoveries of his own. Rather than appeal to ancient authorities, as was common practice for serious scientific inquiry at the time, Steno made his own observations and reached his own conclusions.

Steno finally settled in Italy in 1666. There, the Grand Duke of Tuscany sent him the head of a huge female shark caught near Livorno for dissection. In his findings, published the following year, Steno noted that the sharkette’s teeth were strikingly similar to “tongue stones” found embedded in nearby rock formations.

Contemporary wisdom suggested that fossils (like the tongue stones) grew naturally within rocks. Steno, however, recognized that something different was happening. In 1669, he published his Preliminary Discourse to A Dissertation on A Solid Body Naturally Contained Within A Solid, in which he identified fossils as being left behind by (formerly) living organisms.

Steno’s book also outlined what became the four defining principles of stratigraphy: The Law of Superposition (“…when any given stratum was being formed, all the matter resting upon it was fluid, and, therefore, [at that time] none of the upper strata existed”); The Principle of Original Horizontality (“Strata either perpendicular to […] or inclined to the horizon were at one time parallel to the horizon”); The Principle of Lateral Continuity (“[materials] forming any stratum were continuous over the surface of the Earth unless some other solid bodies stood in the way”); and The Principle of Cross-Cutting Relationships (“If a body or discontinuity cuts across a stratum, it must have formed after that stratum”).

Easily visible stratum at the Cliffs of Moher, Ireland.

Easily visible stratum at the Cliffs of Moher, Ireland.

Stratigraphy in Action

The first practical application of stratigraphy on a large scale was undertaken in the late 18th and early 19th centuries by scientist William Smith, now known as the “Father of English Geology”. Smith created the first geologic map of England and first to recognize the significance of strata and the importance of fossil markers for correlating said strata.

From Smith’s work, stratigraphy was further refined into two related subfields, lithologic stratigraphy (lithostratigraphy) and biologic stratigraphy (biostratigraphy), which are themselves divided into sub-subfields.

Lithostratigraphy deals with the physical contrasts between rock types, and provides the most obvious visible layering. Key concerns in lithologic stratigraphy involve understanding how geometric relationships between different strata form, and what these geometries reveal about the depositional environment.

Biostratigraphy focuses on fossil evidence revealed by strata. Based on Smith’s Principle of Faunal Succession, biologic stratigraphy provides clear evidence for the speciation and extinction of species. Information gleaned from biostratigraphy lead to the development of the geologic time scale in the 19th century.

Photo credit: Allan Henderson / / CC BY

Important People, Important Discoveries

Big John Holybush: 13th Century Scholar, Monk & Astronomer

Johannes de Sacrobosco—whose moniker is not a place, as is often the case with “de something” names, but instead literally translates to “holy bush” (though no one seems to know where “holy bush” came from)—was a scholar, monk, and, most prominently, astronomer. He also spent many years teaching at the University of Paris. He is best remembered for an influential textbook on astronomy and his own remarkably accurate, 300-years-early version of what is now known as the Gregorian calendar.

A Man of Mystery

Very little is actually known about Sacrobosco’s life outside of his written works, especially his early life. He was probably born in England, probably in 1195, and probably died in 1256; however, these assertions have never been solidly confirmed as accurate. Other information suggests that he may have been Scottish, while still other information claims he was born near Dublin, Ireland.

It is likely that he was educated at the University of Oxford, but, as with his birthdate and nation origin, the truth is unknown. One thing that is known for sure is the date of his arrival the University of Paris: 5 June 1221. Whether he was a student or a teacher upon arrival is, also, unclear. Either way, he soon began teaching various forms of mathematics at the University. An epitaph at his gravesite states that he was a computist—one who was an expert at calculating the date of the roaming Easter holiday many years in advance.

Well-Known Genius

Far more certain than Holybush’s origins are his significant contributions to astronomy, mathematics, and, tying in with his notoriety as a computist, the modern calendar.


His best known work, On the Sphere of the World, was published circa 1230. Drawing information from sources including Ptolemy’s Almagest and noted Arabic astronomers Thabit al-Biruni, al-Fargani, ibn Qurra, and al-Urdi, the book gave a readable account of the Ptolemaic universe. The Sphere principally detailed the heavens above, as “sphere” was, at the time, the word for the imaginary backdrop on which the stars in the sky appear, rather than a term describing the earth itself. (It does include a detailed description of Earth as an actual sphere, however.) The book was so well-received and influential that it became required reading for students in all Western European universities for more than 400 years.

Despite that distinction, Sacrobosco’s biggest claim to fame may be his reworking of the Julian calendar. In 1235, Holybush published On Reckoning the Years. In it, he explained the calculations that led him to discover that the Julian calendar had accumulated an error of over ten days. While he had no suggestions for how to rectify the error, he did suggest a new calendar that would eliminate such inaccuracies going forward, a model that very closely resembles the Gregorian calendar (the one we use today)—300 years before its development.

Photo credit: Internet Archive Book Images via / No known copyright restrictions

Historical Science & Technology

What’s Up, Dry Dock?

A dry dock is used for the construction and maintenance of ships and boats. Dry docks are, generally, relatively narrow basins or trenches that are designed to be flooded and drained, as needed. When flooded, boats/ships are floated in or out; when drained, the vessel in question rests on a dry platform so that work can be performed without workers’ trousers getting wet.

The dry dock has been a boon to boaters for centuries. But who first came up with this ingenious solution for boatbuilding and repair?

Whatever Floats Your Boat. (Or Doesn’t)

The earliest record of dry dock use dates back to the 10th century CE, during China’s Song Dynasty. In Dream Pool Essays, scientist and statesman Shen Kuo wrote of the repair of two 200-plus foot long “dragon ships” that had been presented to the Emperor.

After many years, their hulls decayed and needed repairs, but the work was impossible as long as they were afloat. […] Palace official Huang Huai-Hsin suggested a plan: a large basin was excavated […] capable of containing the [ships], and in it heavy crosswise beams were laid upon a foundation of pillars. […] The basin [was] filled with water, after which the ships were towed in above the beams. […] The water was pumped out […] so that the ships rested quite in the air.

A U.S. Naval vessel in dry dock.

A U.S. Naval vessel in dry dock.

The oldest dry dock still in use today was commissioned by some jabroni called Henry VII. Built in 1495 in Portsmouth, Hampshire, England, this ancient dry dock currently houses the HMS Victory, the world’s oldest commissioned warship.

A dry dock is not too be confused with the poop deck which is not to be confused with the latrine. The poop deck is the rear part of the ship and comes from the French word, “la poupe.” If your la poupe’s are too large, make sure to get a plumbing service.

The largest dry dock in the history of mankind was located at the Lisnave Dockyards in Almada, Portugal. In 2000, the dry dock was decommissioned after the Lisnave company relocated to Setúbal, nearly 40 kilometers south on the Portuguese coast. The new world’s-largest-dry dock, measuring 1,200 by 60 meters (72,000 square meters) was built in 2009 by Chantiers de l’Atlantique in Saint-Nazaire, France. The largest dry dock in the United States is operated by Newport News Shipbuilding of Newport News, Virginia; it measures 2,172 feet by 249 feet.

Photo credit: sjrankin via / CC BY-NC

Historical Science & Technology

The Beaufort Scale: Measuring Nautical Wind Speeds Since 1805

The Beaufort Wind Force Scale is an empirical measuring system used to relate wind speed to observable conditions at sea or on land. As it measures wind speed and not force, it’s full name is frightfully inaccurate, and, as such, it is commonly shortened simply “the Beaufort Scale.”

It’s The Royal Irish Navy to the Rescue!

Two hundred ten years ago upon the HMS Woolrich, Irish Royal Navy officer Francis Beaufort devised the wind speed scale that would bear his name forevermore. Developed from existing systems created during the previous century or so, the Beaufort Scale was not officially adopted until the 1830s, when Beaufort served as a top administrator in the Royal Navy. Beaufort later became Rear Admiral Sir Francis Beaufort, so let that be a lesson about how far a little innovation can get a guy.

The Beaufort Scale was first used during the voyage of the HMS Beagle—the same ship that carried Charles Darwin on his exploration of the Galapagos Islands. At the time, weather forecasts were made on the reg by naval officers, but there was no standard scale—subjective terms like “a stiff breeze” were commonly used in these reports. The Beagle’s captain on that voyage, Robert FitzRoy, later founded Britain’s first Meteorological Office, which provided regular weather forecasts using the Beaufort Scale.

Class 12 Beaufort Scale waves on the open sea.

Class 12 Beaufort Scale waves on the open sea.

Beaufort’s Got Class

Original recipe Beaufort Scale did not use actual wind speed numbers, but rather a system of 13 classes that described the qualitative wind conditions in terms of the sails of a frigate. A zero on the Beaufort Scale was “just sufficient to give steerage”; a 12 was a wind “which no canvas sails could withstand.” It obviously covered a broad spectrum of conditions, but was not necessarily specific enough to be useful in all situations.

Nonetheless, the Beaufort Scale became the standard for Royal Navy vessels’ official ship’s log entries in the 1830s; it was adopted for non-naval use in the 1850s.

With the rise of steam powered vessels, the Beaufort scale was modified in 1916 to describe how the sea itself behaved, rather than sails. Rotations to scale number were standardized in 1923, under the direction of the future Sir George Simpson, director of the UK Meteorological Office. In 1946, the Beaufort scale was extended to 17 classes, though the 13 to 17 range were generally used only for extreme weather events like cyclones.

The Beaufort Wind Force Scale was further modified in later decades to improve its accuracy for weather forecasting purposes. Since that time, it has fallen out of use entirely in many countries, where it has been replaced with more “standard” units such as mph or kph. The 2012 edition of the international WMO manual on Marine Meteorological Services defines the Beaufort Scale only up to Class 12.

Photo credit: NOAA / Foter / Public Domain Mark 1.0