Everything Everywhere Daily: History, Science, Geography & More - The Element Mercury

Starting point is 00:00:00 Since the dawn of human history, people have been aware of a seemingly miraculous substance. It was a substance that had the same color as silver, but unlike silver, it wasn't a solid. It was a liquid. Ancient people use this substance as a medicine and as an elixir for long life, something which they got absolutely wrong. Learn more about the element mercury, its history, and its unique properties on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed.

Starting point is 00:00:50 It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. What we know today as Mercury was one of the seven metals of antiquity. These were metals that the ancients knew about because they could be found in their base elemental form. In addition to mercury, there was iron, copper, gold, silver, lead, and tin. Needless to say, mercury was very different from the other six. While it was known, there weren't nearly as many practical uses for it as there were for

Starting point is 00:01:29 the other metals. We should start with the tail of the tape for mercury. Mercury has an atomic number of 80, and thus has 80 protons in its nucleus. This puts it right after platinum and gold on the periodic table. The big thing about Mercury, however, and the one thing that everyone knows if they know anything about Mercury is its low melting point, especially for a metal. Mercury has a melting point of 234.3 Kelvin, or negative 38.8 Celsius, or negative 37.8 Fahrenheit. Its boiling point is 357 Celsius or 674 degrees Fahrenheit.

Starting point is 00:02:09 That means, so long as it isn't bound to some other element in the form of, of a chemical compound, and it's in its elemental form, mercury will be a liquid at almost every temperature that we will ever experience it at. Mercury is rather rare in the earth's crust, but it's far from the rarest element. It's more abundant than silver, gold, or platinum. However, because it doesn't tend to bind with most other elements where it's found, it can be found in high concentrations. While ancient people knew of mercury, it wasn't as if they discovered pools of liquid mercury sitting around. Almost all mercury from the ancient world came from a mineral known as Cinebar, or mercury sulfide. It has the chemical formula of HGS. Cinebar is a very

Starting point is 00:02:55 bright red and was the basis for the pigment known as vermilion. Many ancient people used Cinebar directly as a cosmetic or an ink or in dyes. Many ancient cultures, including China, Egypt, Rome, the Olmecs, Maya, and many others were known. to have used it. Extracting mercury from cinnabar was actually pretty easy, especially compared to how difficult it was to extract other metals from their oars. There were recipes for cold mercury extraction, which involved pulverizing cinnabar in copper and in the presence of an acid, usually vinegar. You can also extract mercury from cinnabar by just heating it, which is how it was extracted at a large scale by the Romans. If you heat cinnabar, mercury vapor will be released, which can then be condensed,

Starting point is 00:03:40 similar to how alcohol is distilled. Evidence of mercury has been found all over the world. The earliest evidence of liquid mercury was found in Egyptian tombs dating back to about 1500 BC. In one of the most incredible stories from ancient China, the first Chinese emperor Chin supposedly had a tomb built with a map of his territories on the floor, and all of the water in his territories was represented by flowing liquid mercury. The tomb, if it does exist, hasn't been discovered yet.

Starting point is 00:04:10 But if it does exist, it may be located somewhere near the terracotta warriors of Cheon. Likewise, in 2014, a large deposit of mercury was found underneath the Temple of the Feathered Spirit in Mexico. However, these uses of mercury were mostly ornamental. The strange liquid properties of mercury gave it mystical attributes, which is why it was so often used by alchemists. Emperor Chin sought to achieve immortality, and he was given treatments by his doctors who believed that mercury was the key to good health. Emperor Chin's doctors couldn't have been more wrong. Not only does Mercury not promote good health, it's actually quite toxic. But more on that in a bit.

Starting point is 00:04:51 The Romans probably did more mercury mining than any other civilization in history up to that point, and they observed that working with Mercury often resulted in illness and death. This became known as Mercurialism. The word Mercury is of Latin origin, and it's named after the planet Mercury, which is named after the Roman god of the same name. The association of the element Mercury with the planet has to do with speed. Mercury is the fastest planet, and Mercury was the god of messages and journeys. The element of Mercury, often known as quicksilver, was associated with speed because of how it would move.

Starting point is 00:05:28 The chemical symbol for Mercury is HG, which comes from the Romanized Greek word hydragyram, which just means water silver. One of the biggest advances in Mercury was the discovery in the 16th century that mercury could be used to process silver. Dubbed the patio process, it was developed by Bartolome de Medina in Pachuca, Mexico in 1554. The patio process used Mercury to create an amalgam with silver. An amalgam is any metallic alloy with mercury. Mercury is particularly fond of creating amalgams with gold and silver, so it proved to be an excellent way to extract silver from ore.

Starting point is 00:06:09 The patio process largely replaced smelting in the production of silver. Given the large amounts of silver the Spanish were mining in the new world, it required large amounts of mercury for the patio process. The primary source of mercury was a single mine in Almaden, Spain, which was the largest deposit of mercury in the form of cinnabar on earth. The mine in Almaden had been in service for over 2,000 years, but it was only starting in the 16th century that the mine saw its greatest output. I actually had the pleasure of visiting the mine in Almedan in 2018. The mine actually hasn't been in operation since 2002, and it was open to the

Starting point is 00:06:48 public in 2006. Today, it and another mercury mine in Slovenia are both world heritage sites. The mercury produced in Almedan was then shipped to the new world to process the silver, which was then shipped back to Spain. The use of mercury for the amalgamation of silver and gold was by far the largest use of mercury for centuries. However, there were eventually more uses found for the unique substance. In 1643, the Italian scientist Evangelista Torricelli invented a device to measure air pressure. It was a U-shaped tube that was closed on one end and open on the other, with a liquid in the middle that would move based on the pressure from the open end of the tube. Water was originally used as the liquid, but it required an enormous tube. With heavier

Starting point is 00:07:34 mercury, it only required a tube a fraction of the size. In 1714, Daniel Gabriel Fahrenheit, a Polish physicist living in the Netherlands, invented a device that consisted of mercury in a closed tube that would change its level based on temperature. The mercury-in-glass thermometer was the most accurate temperature measuring device created at that time. In the 19th century, mercuric nitrate was used to produce a superior felt that was used in hats. The constant exposure of mercury vapors by hatmakers often led to mercury poisoning.

Starting point is 00:08:09 And this is where the phrase, mad as a hatter, came from. The 20th century saw even more uses for mercury. One of the most important uses was in electronic devices. The fact that mercury was both an electrical conductor and a liquid allowed it to be used for many different applications. One of the biggest uses was in electrical switches. Depending on the position of the switch, mercury could flow from one end of the switch to the other where there were two electrodes, and mercury would help complete the circuit. Mercury vapor fluorescent lights were developed, which were more efficient than incandescent lights. When an electrical current passes through mercury vapor, it produces ultraviolet light.

Starting point is 00:08:47 When the ultraviolet rays hit the phosphor coating on a tube, it causes it to fluoresce. In the mid-20th century, mercury was used in non-rechargeable batteries that were very popular during and immediately after World War II. The biggest use for mercury during the 20th century was for the chloral alkali process. The chloral alkali process was used to separate chlorine and sodium in a brine solution. Amalgams of mercury, usually with silver, tin, and copper have been used in dentistry to fill cavities. Mercury fulminate is an explosive that was often used as a primer in bullets. And on top of all this, mercury was used in a host of chemical products, including paints and cleaning products.

Starting point is 00:09:29 One of the most innovative uses of Mercury was as a mirror in telescopes. Because of its silvery reflective surface, mercury could be used as a telescope mirror. Isaac Newton discovered that if you rotate it to liquid, the surface of the liquid would form a parabola as the edges of the liquid rose up along the side of the rim. If you had a very large container of Mercury and spun it, you would be able to create a very powerful lens. And this is exactly what some astronomers did. They created a very large aperture telescope lens using Mercury at just a fraction of the cost of traditional telescopes. There is, of course, a massive downside to this method.

Starting point is 00:10:10 You can't really point a liquid mirror in any direction you want. In fact, there's only one direction you can point it, straight up. The University of British Columbia's massive six-meter telescope, known as the Large Zenith Telescope, allows for a massive mirror at a fraction of the cost of traditional telescopes. by using mercury. Mercury was a somewhat common ingredient in many different industrial and commercial products throughout the 20th century. However, there was a big problem.

Starting point is 00:10:40 While mercury poisoning had been known for centuries, medical professionals began to understand just what the dangers were of mercury poisoning. I'm old enough that I can remember mercury thermometers, and in a few cases, how they would break and you could play with mercury. It turned out that this was an incredible. dumb thing to do. Mercury can quite easily vaporize, which means that even if you work with liquid mercury, you run the risk of mercury poisoning. All of the mercury in so many products raised the level of mercury poisoning for everyone in the population. However, as a heavy toxic

Starting point is 00:11:17 metal that could uniquely vaporize compared to other metals, mercury could accumulate in life forms that ingested it, and this was especially problematic in fish, as mercury would accumulate at higher trophic levels of the food chain. Lower levels of animals may have only had a small amount of mercury. However, as those fish were eaten and were subsequently eaten by other fish, mercury levels would accumulate. Fish like tuna can have higher levels of mercury as can dolphins and whales. In 2008, actor Jeremy Piven was diagnosed with mercury poisoning after he was found with mercury

Starting point is 00:11:51 levels five to six times higher than normal. It turned out, he'd been eating sushi twice a day, every day for 20 years. Mercury is a fascinating substance. It's heavy weight and the fact that it's a liquid at room temperature makes it extremely useful for certain applications. However, it's also a highly toxic substance. It's so toxic that it's been removed from almost all common commercial products.

Starting point is 00:12:18 And that's the fact that probably wouldn't have survived the people who did work with Mercury almost 2,000 years ago. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Peter Bennett and Cameron Kiever. I wanted to give a big thanks to everyone who supports the show on Patreon. Your support helps me put out a new show every day. And if you're interested in Everything Everywhere Daily merchandise, Patreon is currently the only place where it's available.

Starting point is 00:12:48 And if you'd like to talk to other listeners of the show and get notified of future episodes and projects, please join my Facebook group or Discord server. Links to everything are in the show notes. Thank you.

Everything Everywhere Daily: History, Science, Geography & More - The Element Mercury

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