Salt, NaCl, is an ionic compound made of sodium and chloride ions. Sea salt is salt produced from the evaporation of seawater. It has been important to humans for thousands of years because all life has evolved to depend on it. Humans, like all life, need dietary salt to survive. Salt's ability to preserve food was a founding contributor to civilization. It helped to eliminate dependence on the seasonal availability of food and made it possible to ship some foods over long distances. However, salt was difficult to obtain, so it was a highly valued trade item and 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.
Sea salt is mentioned in the Vinaya Pitaka, a Buddhist scripture compiled in the mid-5th century BC.The principle of production is evaporation of the water from the sea brine. In warm and dry climates this may be accomplished entirely by using solar energy, but in other climates, fuel sources have been used. Modern sea salt production is almost entirely found in Mediterranean and other warm, dry climates
All through history, availability of salt has been pivotal to civilization. In Britain, the suffix "-wich" in a place name means it was once a source of salt, as in Sandwich and Norwich. The Natron Valley was a key region that supported the Egyptian Empire to its north because it supplied it with a kind of salt that came to be called by its name, natron
Salt was of high value to the Hebrews, Greeks, the Chinese, Hittites and other peoples of antiquity. Aside from being a contributing factor in the development of civilization, salt was also used in the military practice of salting the earth by various peoples, beginning with the Assyrians. In the early years of the Roman Republic, with the growth of the city of Rome, roads were built to make transportation of salt to the capital city easier. An example was the Via Salaria (originally a Sabine trail), leading from Rome to the Adriatic Sea. The Adriatic, having a higher salinity due to its shallow depth, had more productive solar ponds compared with those of the Tyrrhenian Sea, much closer to Rome. The word "salary" comes from the Latin word for salt.
During the late Roman Empire and throughout the Middle Ages salt was a precious commodity carried along the salt roads into the heartland of the Germanic tribes. Caravans consisting of as many as forty thousand camels traversed four hundred miles of the Sahara bearing salt to inland markets in the Sahel, sometimes trading salt for slaves: Timbuktu was a huge salt and slave market.
Salt in Chinese history was both a driver of technological development and a stable source of revenue for the imperial government.
Solnitsata, the earliest known town in Europe was built around a salt production facility. Located in present-day Bulgaria, archaeologists believe the town accumulated wealth by supplying salt throughout the Balkans.
In the Old Testament, Mosaic law calls for salt to be added to all burnt animal sacrifices (Lev. 2:13) and compares the priestly covenant between God and the kohen patrilineal descendants of Ahron to salt.
The Book of Ezra (550 BC to 450 BC) associated accepting salt from a person with being in that person's service. In Ezra 4:14, the adversaries of Ezra and company, in their letter of complaint to Artaxerxes I of Persia explain their loyalty to the King. When translated, it is either stated literally as "because we have eaten the salt of the palace" or more figuratively as "because we have maintenance from the king".
Salt is used as a metaphor in the Bible. In the New Testament, Matthew 5:13, Jesus said, "You are the salt of the earth". He added that if the salt loses its flavor, it is good for nothing but to be trampled. Jesus said this to show his disciples how valuable they were, and this saying is used today to describe someone who is of particular value to society. In addition, the preservative quality of salt is in view here to show how the disciples were called to preserve the society and the world around them from moral decay. On another occasion, according to the Gospels, Jesus commanded his followers to "...have salt within them."
In Luke 14:34-35 Jesus concludes a series of parables on the cost of following him with the parable of spent salt. It seems that those who follow him are to be like the salt. From this we learn that those who follow him should expect to be spent, as chunks of salt after much use. Furthermore, they should prepare to be useful until the end, for the long haul. In this parable, it is good to be used as salt and bad to become useless salt. This illustration ties in with the two preceding ones (Luke 14:28-33) of counting the cost: the disciples must prepare, by counting the cost, to be salty for as long as they are needed.
Salt created and destroyed empires. The salt mines of Poland led to a vast kingdom in the 16th century, only to be demolished 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.
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.
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 outcomes 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, 180 miles long and 45 wide, supposed to lie near the Missouri River, which would have been of immense value, as a reason for their expedition.
Salt was a crucial resource during the Civil War. Salt not only preserved food in the days before refrigeration, but was also vital in the curing of leather. Union general William Tecumseh Sherman once said that "salt is eminently contraband", as an army that has salt can adequately feed its men.
The most important saltworks for the Confederacy were at Saltville, Virginia. In late 1864, the Union army twice advanced to capture the saltworks, as it was the last prominent source of salt for the eastern Confederate states. The October 1864 Battle of Saltville I saw the Confederate able to repulse the charge, but the next December in the Battle of Saltville II Union forces under George Stoneman managed to destroy the vital saltworks. Two months later the salt works were back to work for the Confederacy, although the destroyed railroad system around the area hampered its distribution.
In Georgia, the price of salt depended on one's family circumstances. Heads of families could purchase a half-bushel of salt for $2.50. If a widow had a son in the Confederate army, the price was only $1.00. But if the widow's husband served his nation, the price was free. Local court clerks sent the salt requests to the state government, which in turn allotted the salt to the counties as requested.
Florida's greatest contribution to the Confederate war effort was in producing salt. With a total investment of $10 million, Floridian salt plants worked 24 hours a day boiling salt from sea water, mostly in the area between Saint Andrews Bay and St. Marks, Florida. Occasionally, Union forces came ashore just to destroy the boilers. The Confederate law made those involved in salt-making immune to being drafted, making it a popular profession in war-time Florida; the estimated total workers involved was 5,000.
One way Southern families acquired salt was to boil the dirt in areas where they had previously cured meats. They would dig it out, and strain it.
Avery Island, off the Louisiana coast, gave the Confederacy a huge supply of rock salt until the Union captured it. However, Confederates never realized that similar structures to the Avery Island salt dome were all along the Louisiana and Texas coasts of the Gulf of Mexico, and could have provided a more easily acquired source of salt.
The Moscow uprising of 1648, sometimes known as the salt riot, started because of the government's replacement of different taxes with a universal salt tax for the purpose of replenishing the state treasury after the Time of Troubles. This drove up the price of salt, leading to violent riots in the streets of Moscow. The riot was an early challenge to the reign of Alexei I, eventually resulting in the exile of Alexei's advisor Boris Morozov.
The Salt March, also known as the Dandi March and the Dandi Satyagraha, was an act of nonviolent civil disobedience in colonial India initiated by Mohandas Karamchand Gandhi to produce salt from the seawater in the coastal village of Dandi, as was the practice of the local populace until British officials introduced taxation on salt production, deemed their sea-salt reclamation activities illegal, and then repeatedly used force to stop it. The 24-day march began on 12 March 1930 as a direct action campaign of tax resistance and nonviolent protest against the British salt monopoly, and it gained worldwide attention which gave impetus to the Indian independence movement and started the nationwide Civil Disobedience Movement.
Salt, salt production, and salt taxes played key roles in Chinese history, economic development, and relations between state and society. The lure of salt profits led to technological innovation and new ways to organize capital. Debate over government salt policies brought forth conflicting attitudes toward the nature of government, private wealth, the relation between the rich and the poor, while the administration of these salt policies was a practical test of a government's competence.
Because salt is a necessity of life, the tax on it (often called the salt gabelle) had a broad base and could be set at a low rate and still be one of the most important sources of government revenue. In early times, governments gathered salt revenues by managing production and sales directly. After innovations in the mid-8th century, imperial bureaucracies reaped these revenues safely and indirectly by selling salt rights to merchants who then sold the salt in retail markets. Private salt trafficking persisted because monopoly salt was more expensive and of lower quality, while local bandits and rebel leaders thrived on salt smuggling. Over time, however, this basic system of bureaucratic oversight and private management yielded revenue second only to the land tax, and, with considerable regional variation and periodic reworking, remained in place until the mid-20th century.
Salt also played a role in Chinese society and culture. Salt is one of the "seven necessities of life" mentioned in proverbs and "salty" is one of the "five flavors" which form the cosmological basis of Chinese cuisine. Song Yingxing, author of the 17th-century treatise, The Exploitation of the Works of Nature explained the essential role of salt:
“as there are five phenomena in weather, so are there in the world five tastes… A man would not be unwell if he abstained for an entire year from either the sweet or sour or bitter or hot, but deprive him of salt for a fortnight, and he will be too weak to tie up a chicken…”
A salt road (also known as a salt route, salt way, salt-way, or salt trading route) is any of the prehistoric and historical trade routes by which essential salt has been transported to regions that lacked it (see History of salt).
From the Bronze Age (in the 2nd millennium BC) fixed transhumance routes appeared, like the Ligurian drailles that linked the maritime Liguria with the alpages, long before any purposely-constructed roadways formed the overland routes by which salt-rich provinces supplied salt-starved ones.
The Via Salaria, an ancient Roman road in Italy, eventually ran from Rome (from Porta Salaria in the Aurelian Walls) to Castrum Truentinum (Porto di Ascoli) on the Adriatic coast - a distance of 242 kilometers (150 mi). A modern road by this name, part of the SS4 highway, runs 51 kilometers (32 mi) from Rome to Osteria Nuova in Orvieto.
The Old Salt Route, about 100 kilometers (62 mi), was a medieval route in northern Germany, linking Lüneburg (in Lower Saxony) with the port of Lübeck (in Schleswig-Holstein), which required more salt than it could produce itself. Lüneburg, first mentioned in the 10th century, grew rich on the salterns surrounding the town. Traders shipped salt via Lauenburg, to Lübeck, which supplied all the coasts of the Baltic Sea. Lüneburg and its salt were major factors of power and wealth of the Hanseatic League. After a long period of prosperity, its importance declined after 1600. The last of the salt mines were closed in 1980, ending the thousand-year tradition.
In France, the salt route was longer than a portage between navigable streams. Salt unloaded at the ports of Nice and Ventimiglia could travel by two salt roads leading away from the coastal area, from Nice up the Vésubie valley, via Saint-Martin-Vésubie at the head of the valley, or from Ventimiglia inland through the Roya Valley, over the Col de Tende pass and into Piedmont.
In Ethiopia blocks of salt, called amoleh, were carved from the salt pans of the Afar Depression, especially around Lake Afrera, then carried by camel west to Atsbi and Ficho in the highland, whence traders distributed them throughout the rest of Ethiopia, as far south as the Kingdom of Kaffa.
Before the People's Republic of China annexed Tibet and closed the borders in the 1950s, salt trade between Nepal and Tibet crossed passes through the Himalayas such as the gorges of the upper Karnali and Gandaki rivers. Caravans of pack animals brought rice up from Nepal's Terai and lower hills in exchange for salt from dry lakes on the Tibetan Plateau.
Rivers and ports
The salt highways of Europe were the navigable rivers, where by medieval times shipments of salt coming upstream passed rafts and log-trains of timber, which could only be shipped downstream. And even along Europe's coasts, once long-distance trade was revived in the 11th century, the hot and sunny south naturally outproduced the wet north. By the Late Middle Ages the expanding fishing fleets of the Low Countries required more salt than could be produced locally; the balance was made up with salt from the Iberian Peninsula: "The United Provinces could have been brought to their knees if their supplies of salt had been blocked at the end of the sixteenth century. Spain did no more than dream of this," Fernand Braudel has written. In Ming China, salt, as well as rice, was shipped from south to north, along with the Imperial Canal as far as Beijing.
In France, a major source of marine salt with access to expansive hinterlands in need of it was the wetlands region in Languedoc called the Camargue; from the salt pans called salines, convoys of boatloads of salt could be carried up the Rhone to Seyssel where it had to be off-loaded and carried by mule train inland to the little village of Regonfle near Geneva, where it rejoined a waterway.
Of the early modern period in Europe, Fernand Braudel remarked that in spite of the flux and reflux of economics:
"No salt mine was ever abandoned and the scale of the equipment needed put these mines in the hands of merchants from very early days. Salt-marshes, on the other hand, were exploited by artisanal methods: the merchants took control only of transport and marketing, both in Setúbal in Portugal and in Peccais in Languedoc. Salt marketing was probably quite big business along the Atlantic seaboard or the Rhône valley."
The vast interior of Poland was salt-starved, its maritime districts lying under rainy skies and fronting the Baltic Sea. By medieval times the process of mining for fossil salt supplemented the age-old techniques of evaporating sea salt in tidal pans. By the 14th century, at Wieliczka near Kraków, Braudel reports that peasant extraction of salt from brine evaporated in large shallow iron pans had been eliminated by the early industrialization of salt mining. "Galleries and shafts were now dug to a depth of 300 meters, and enormous winches powered by teams of horses brought blocks of salt to the surface. At its peak, production stood at 40,000 tons a year and the mines employed 3,000 workers. By 1368, the cooperation of the Polish state had been obtained."
Salt has long held an important place in religion and culture. Greek worshippers consecrated salt in their rituals. Jewish Temple offerings included salt; on the Sabbath, people of the Jewish faith still dip their bread in salt as a remembrance of those sacrifices. In the Old Testament, Lot’s wife was turned into a pillar of salt. Author Sallie Tisdale notes that salt is as free as the water suspending it when it’s dissolved, and as immutable as stone when it’s dry.
Covenants in both the Old and New Testaments were often sealed with salt: the origin of the word “salvation.” In the Catholic Church, salt is or has been used in a variety of purification rituals. In fact, until Vatican II, a small taste of salt was placed on a baby’s lip at his or her baptism. Jesus called his disciples “the Salt of the Earth.” In Leonardo DaVinci’s famous painting, “The Last Supper,” Judas has just spilled a bowl of salt, which is known as a portent of evil and bad luck. To this day, the tradition ensures that when people spill salt, they should throw a pinch over their left shoulders to ward off any devils that may be lurking behind.
In Buddhist tradition, salt repels evil spirits, which is why it is customary to throw salt over your shoulder before entering your house after a funeral: it scares off any evil spirits that may be clinging to your back.
Shinto religion also uses salt to purify an area. Before sumo wrestlers enter the ring for a match—which is actually an elaborate Shinto rite—a handful of salt is thrown into the center to drive off malevolent spirits.
In the Southwest, the Puebloans worship the Salt Mother. Other native tribes had significant restrictions on who was permitted to eat salt. Hopi legend holds that the angry Warrior Twins punished mankind by placing valuable salt deposits far from civilization, requiring hard work and bravery to harvest the precious mineral.
In 1933, the Dalai Lama was buried sitting up in a bed of salt.
Today, a gift of salt endures in India as a potent symbol of good luck and a reference to Mahatma Gandhi’s liberation of India, which included a symbolic walk to the sea to gather tax-free salt for the nation’s poor.