We Love Salt: We have been adding it to our food for thousands, possibly millions, of years. Here’s a new and improved salt shaker patented in 1892. Credits: Scientific American, July 23, 1892
Salt: Historical Notes from Scientific American
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We Love Salt: We have been adding it to our food for thousands, possibly millions, of years. Here's a new and improved salt shaker patented in 1892. Scientific American, July 23, 1892
Salt and Water: Salt in seawater or from brine from underground needs to be separated from its water. This handy evaporating table is powered by heat, from 1864. Modern methods also use partial vacuum to reduce fuel costs... Scientific American, October 22, 1864
Salt Mines: This diagram from 1926 shows a salt mine used by native Americans near the Grand Canyon. Archaeological remains indicate it may have been in use for 2,000 years. Scientific American, August 1926
Rock Salt: This drawing of a factory worker in Cheshire, England, in 1890 shows fine-grained rock salt taken from evaporation pans and poured into moulds. When dry, these lumps were sold for table salt... Scientific American Supplement, April 19, 1890
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Brine Pipelines, China: In Tzuliutsing, Szechuan, China, wells brought brine to the surface, where it was piped through extensive networks of bamboo pipes to evaporation houses. This image goes with the image printed in the 50, 100 & 150 Years Ago column... Scientific American Supplement, November 18, 1916
Windmill, China: These windmills were extensively used in China in 1901 to pump seawater into evaporation ponds. Scientific American Supplement, May 11, 1901
Salt Tax: Sodium Chloride is a necessity and a flavor enhancer. Its production was heavily taxed in China. Here, a government official oversees the weighing of this valuable commodity (original photograph from 1916)... Scientific American Monthly, May 1921
Salt in India: “One of the most important industries in India.” In 1931 1,000,000 tons of salt came from seawater near Bombay and Madras, 500,000 tons of rock salt were produced in the Punjab and Rajputana, and 500,000 tons were imported, mostly from Egypt... Scientific American, April 1931
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Labor and Salt: Alvarado, 20 miles from San Francisco, 1905. Salt was made from seawater at a fifth the cost of rock salt from the Rocky Mountains. Windmills raised brine and cheap hand labor used wheelbarrows to move the salt... Scientific American, April 1, 1905
Electricity for Salt: Moving brine from a concentration pond to an evaporation pond with an electrically driven motor and wheel, near San Francisco, 1929. The finished product was moved by gasoline engines or steam trains... Scientific American, February 1929
For all of our early-21st-century hand-wringing about how we all eat too much salt, sodium chloride is a vital chemical for human metabolism and we have evolved to crave it. It is claimed that salt is one of the founding pillars of civilization, because it enabled food to be preserved, it was one of the earliest goods to be manufactured, and it was one of the first articles to be traded.
Salt has been produced for centuries from one of three basic methods: by evaporation of sea water (because there are 36 quadrillion tons of salt dissolved in ocean waters), by digging it out of the ground, or by extraction of crystallized salt as brine (because there are 1 quadrillion tons of rock salt available in the earth’s crust). These days global annual production of salt (for eating, industry and melting ice on roadways) is currently over 200 million tons.
Here are some images from the Archives of Scientific American, showing a short glimpse of the history of this storied chemical compound. And as you peruse these images, perhaps consider that as long as there has been salt production, it has always been big business.
