Salt. A most common, and darned near ubiquitous mineral that barely deserves notice, right? Well, as cheap and accessible as salt appears to be, it is actually one of the most important substances known to man. In fact, it could be argued that human civilization as we know it owes its very existence to this seemingly unimportant substance!
I’ve wanted to do a post on salt for some time now, after seeing several television documentaries on the uses and production of it a while back. But I held off, frankly, because the subject is just so damned big! Well, I was feeling energized enough when I woke up this morning (which most definitely has NOT lasted) to finally give it a go.
Let’s begin with a little “mining” for data, shall we? Trust me, the following information merely “scratches the surface” of what’s available on this amazing subject! Note: The bold highlighting is mine.
Salt, NaCl, is a chemical compound made of sodium and chloride which has been exceptionally important to humans for thousands of years. Salt’s ability to preserve food was a foundation of civilization. It helped to eliminate the dependence on the seasonal availability of food and it allowed travel over long distances. However, salt was difficult to obtain, and so it was a highly valued trade item to the point of being considered a form of currency by certain peoples. Many salt roads, such as the via Salaria in Italy, had been established by the Bronze age.
Today, salt is almost universally accessible, relatively cheap and often iodized.
Common salt is a mineral substance composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of ionic salts; salt in its natural form as a crystalline mineral is known as rock salt or halite. Salt is present in vast quantities in the sea where it is the main mineral constituent, with the open ocean having about 35 grams (1.2 oz) of solids per litre, a salinity of 3.5%. Salt is essential for animal life, and saltiness is one of the basic human tastes. The tissues of animals contain larger quantities of salt than do plant tissues; therefore the typical diets of nomads who subsist on their flocks and herds require little or no added salt, whereas cereal-based diets require supplementation. Salt is one of the oldest and most ubiquitous of food seasonings, and salting is an important method of food preservation.
Some of the earliest evidence of salt processing dates back to around 6,000 years ago, when people living in Romania were boiling spring water to extract the salts; a saltworks in China has been found which dates to approximately the same period. Salt was prized by the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites and the Egyptians. Salt became an important article of trade and was transported by boat across the Mediterranean Sea, along specially built salt roads, and across the Sahara in camel caravans. The scarcity and universal need for salt has led nations to go to war over salt and use it to raise tax revenues. Salt is also used in religious ceremonies and has other cultural significance.
Salt is produced from salt mines or by the evaporation of seawater or mineral-rich spring water in shallow pools. Its major industrial products are caustic soda and chlorine, and it is used in many industrial processes and in the manufacture of polyvinyl chloride, plastics, paper pulp and many other products. Of the annual production of around two hundred million tonnes of salt, only about 6% is used for human consumption; other uses include water conditioning processes, de-icing highways and agricultural use. Edible salt is sold in forms such as sea salt and table salt which usually contains an anti-caking agent and may be iodised to prevent iodine deficiency. As well as its use in cooking and at the table, salt is present in many processed foods. Too much sodium in the diet raises blood pressure and may increase the risk of heart attacks and strokes. The World Health Organization recommends that adults should consume less than 2,000 mg of sodium which is equivalent to 5 grams of salt per day.
Sodium chloride, also known as salt, common salt, table salt or halite, is an ionic compound with the formula NaCl, representing equal proportions of sodium and chlorine. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms. In the form of edible or table salt it is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses. A second major consumer of sodium chloride is deicing of roadways in sub-freezing weather.
Sodium is a chemical element with the symbol Na (from Latin: natrium) and atomic number 11. It is a soft, silver-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. The free metal does not occur in nature, but instead must be prepared from its compounds; it was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Sodium is the sixth most abundant element in the Earth’s crust, and exists in numerous minerals such as feldspars, sodalite and rock salt (NaCl). Many salts of sodium are highly water-soluble, and their sodium has been leached by the action of water so that sodium and chlorine (Cl) are the most common dissolved elements by weight in the Earth’s bodies of oceanic water.
Many sodium compounds are useful, such as sodium hydroxide (lye) for soap-making, and sodium chloride for use as a de-icing agent and a nutrient (edible salt). Sodium is an essential element for all animals and some plants. In animals, sodium ions are used against potassium ions to build up charges on cell membranes, allowing transmission of nerve impulses when the charge is dissipated. The consequent need of animals for sodium causes it to be classified as a dietary inorganic macro-mineral.
Chlorine is a chemical element with symbol Cl and atomic number 17. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine. The element is a yellow-green gas under standard conditions, where it forms diatomic molecules. Chlorine has the highest electron affinity and the fourth highest electronegativity of all the reactive elements. For this reason, chlorine is a strong oxidizing agent. Free chlorine is rare on Earth, and is usually a result of direct or indirect oxidation by oxygen.
The most common compound of chlorine, sodium chloride (common salt), has been known since ancient times. Around 1630 chlorine gas was first synthesized in a chemical reaction, but not recognized as a fundamentally important substance. Characterization of chlorine gas was made in 1774 by Carl Wilhelm Scheele, who supposed it to be an oxide of a new element. In 1809 chemists suggested that the gas might be a pure element, and this was confirmed by Sir Humphry Davy in 1810, who named it from Ancient Greek: χλωρóς khlôros “pale green”.
Nearly all chlorine in the Earth’s crust occurs as chloride in various ionic compounds, including table salt. It is the second most abundant halogen and 21st most abundant chemical element in Earth’s crust. Elemental chlorine is commercially produced from brine by electrolysis. The high oxidizing potential of elemental chlorine led commercially to free chlorine’s bleaching and disinfectant uses, as well as its many uses of an essential reagent in the chemical industry. Chlorine is used in the manufacture of a wide range of consumer products, about two-thirds of them organic chemicals such as polyvinyl chloride, as well as many intermediates for production of plastics and other end products which do not contain the element. As a common disinfectant, elemental chlorine and chlorine-generating compounds are used more directly in swimming pools to keep them clean and sanitary.
In the form of chloride ions, chlorine is necessary to all known species of life. Other types of chlorine compounds are rare in living organisms, and artificially produced chlorinated organics range from inert to toxic. In the upper atmosphere, chlorine-containing organic molecules such as chlorofluorocarbons have been implicated in ozone depletion. Small quantities of elemental chlorine are generated by oxidation of chloride to hypochlorite in neutrophils, as part of the immune response against bacteria. Elemental chlorine at high concentrations is extremely dangerous and poisonous for all living organisms, and was used in World War I as the first gaseous chemical warfare agent.
Salt has played a prominent role in determining the power and location of the world’s great cities. Liverpool rose from just a small English port to become the prime exporting port for the salt dug in the great Cheshire salt mines and thus became the entrepôt for much of the world’s salt in the 19th century.
Salt created and destroyed empires. The salt mines of Poland led to a vast kingdom in the 16th century, only to be destroyed when Germans brought in sea salt (which most of the world considered superior to rock salt). Venice fought and won a war with Genoa over salt. However, Genoese Christopher Columbus and Giovanni Caboto would later destroy the Mediterranean trade by introducing the New World to the market.
Cities, states and duchies along the salt roads exacted heavy duties and taxes for the salt passing through their territories. This practice even caused the formation of cities, such as the city of Munich in 1158, when the then Duke of Bavaria, Henry the Lion, decided that the bishops of Freising no longer needed their salt revenue.
The gabelle — a hated French salt tax — was enacted in 1286 and maintained until 1790. Because of the gabelles, common salt was of such a high value that it caused mass population shifts and exodus, attracted invaders and caused wars.
In American history, salt has been a major factor in outcome of wars. In the Revolutionary War, the British used Loyalists to intercept Revolutionaries’ salt shipments and interfere with their ability to preserve food. During the War of 1812, salt brine was used to pay soldiers in the field, as the government was too poor to pay them with money. Before Lewis and Clark set out for the Louisiana Territory, President Jefferson in his address to Congress mentioned a mountain of salt supposed to lie near the Missouri River, which would have been of immense value, as a reason for their expedition. (By 1810, new discoveries along the Kanawha and Sandy Rivers had greatly reduced the value of salt.)
During India’s independence movement, Mohandas Gandhi organized the Salt Satyagraha protest to demonstrate against the British salt tax.
Wich and wych are names associated (but not exclusively) with brine springs or wells in England. Originally derived from the Latin vicus, meaning “place”, by the 11th century use of the ‘wich’ suffix in placenames was associated with places with a specialised function including that of salt production. Several English places carry the suffix and are historically related to salt, including the four Cheshire ‘witches’ of Middlewich, Nantwich, Northwich and Leftwich (a small village south of Northwich), and Droitwich in Worcestershire. Middlewich, Nantwich, Northwich and Droitwich are known as the “Domesday Wiches” due to their mention in the Domesday Book, “an indication of the significance of the salt-working towns in the economy of the region, and indeed of the country”.
Monopolies over salt production and trade were essential aspects of government revenue in imperial China and most of the 20th century.
During modern times, it became more profitable to sell salted food than pure salt. Thus sources of food to salt went hand in hand with salt making. The British controlled saltworks in the Bahamas as well as North American cod fisheries. The search for oil in the late 19th and early 20th centuries used the technology and methods pioneered by salt miners, even to the degree that they looked for oil where salt domes were located.
Anyway, I was reminded of all that when I saw these amazing images on Amusing Planet…
Images reblogged from A Psychedelic Salt Mine in Yekaterinburg on Amusing Planet
Which then, of course, lead me to find these beauties on The Atlantic…
Images reblogged from The Strange Beauty of Salt Mines on The Atlantic
In short, the innocuous looking, white granular substance we know today as “salt” historically has been so essential to all life as to be of the utmost value. We are fortunate, indeed, that in the United States it has never been subjected to discriminatory taxes, and that in North America it is plentiful and one of the most easily obtainable and least expensive of our necessities.
Clearly, salt is a subject that deserves far more respect than it’s commonly given! 🙂
I want ice water.
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