By D. Scott Nickerson, M.D.
As the Nickerson Family Association’s project to rescue the 1829 Caleb Nickerson House got underway, I noticed the biographical vignette about Caleb #219 in The Nickerson Family Part 2. I was curious about the mention in his will of “2800 feet of saltworks, store and mills.” As I investigated more, I found that the production of salt by solar evaporation was a huge industry on Cape Cod in the first half of the 19th century, responsible for creation of a huge amount of wealth for Nickersons and others in the small towns on the Lower and Mid Cape. It worked like this:
With the Revolutionary War came a British blockade of the coast, terminating the import of salt necessary to the preservation of the catch of the fishing fleets. The fishing industry came to a screeching halt and boats sat at dock, rotting, for a decade. A new, local source of salt was necessary and Yankee ingenuity soon developed an answer. There was salt in the sea, wind to drive windmills, lumber available to harvest, and sun to evaporate water. By 1800 an effective and economical process had been worked out.
Large evaporating vats were built, holding about 12 inches depth of water, with covers on rollers or pivots to be moved into place when rainy weather required. Water was pumped by wind mills into the highest of a series of three vats where detritus and organic matter settled out. After several weeks, the now-concentrated brine was drained into the second “pickle vat.” The wind and warm Cape Cod sun continued to evaporate water until lime, calcium sulfate, precipitated from the concentrated solution. This could be used to fertilize the fields. The remaining liquid was then drained by gravity into a third adjacent lower vat where evaporation continued. The desired salt, sodium chloride, crystallized and dropped out of solution, then was raked and shoveled into wheelbarrows for transport to sheltered drying and storage areas. The remaining liquid contained laxative salts known as Glauber’s Salt and Epsom Salts (magnesium and sodium sulfates), another saleable product, which was induced to crystallize out of solution later in the cold weather of winter.
Think about your operating costs for such a business. The raw material, seawater itself, was free. So was the wind, which powered the windmills to pump the water or grind the salt. Gravity moved the seawater and liquid concentrates from one place to another. The sun itself provided the heat energy driving evaporation. The major costs were the initial investment in building vats, covers, and windmills. Some business, eh?
The vats could be tended by old men, women and children who were often family members, and would scurry out to quickly cover the vats when rain threatened. The salt-making season lasted April to October. It required four-to-six weeks to take a batch from seawater to dried salt giving about six cycles per year. Large areas of the low “salt marsh” ground on the Cape seashores were covered with the vats, windmills, salt storehouses, and salt grinding mills. An 1831 map of Chatham shows at least 40 different sites in the town, covering over 75 Acres, and Nickersons owned many of them. David Crowell reported that in 1835 he could see 28 windmills on the shores of Ryders Cove. It must have been quite picturesque as many travelers of the time, including Henry Thoreau, commented.
An annual profit of 25-35 percent could be realized on the initial investment cost. If hurricanes and storms didn’t tear up the saltworks, you needed to cover only labor cost and repairs and the profits kept on coming.
Your saltworks could produce annually about two bushels of sodium chloride per year per superficial foot (10 sq. feet) of vat evaporating surface. Salt prices varied between 50 cents and $8 per bushel in these times, with especially high prices during the war of 1812 when a British embargo and sea blockade was again in effect. Laxative salt sales yielded an equivalent amount. Calculations of the area of vat surface times expected production at 50 cents/bushel indicate a profit over the 50 years before 1850 of about $500 million to $1 billion in today’s dollars using a price deflator of $25 today = $1 in 1820. The salterns were a very large and lucrative industry. These 19th century saltworks of Cape Cod helped supply much of the capital which allowed our fledgling nation to become an industrial powerhouse.
By about 1850 it was all over. Congress lifted a tariff on imported salt. Massachusetts repealed a state bounty on salt production, and the Erie Canal opened in 1826 to allow cheap transport of salt produced from mines and concentrated salt springs in western New York. Extensive storm damage in 1815, 1841, then 1851 and 1856 could not be repaired economically as timber was now more distant and transport expensive. Many damaged works were never rebuilt and the last operations limped on into the 1880s. No evaporative saltworks exist today anywhere in the Cape. The Dennis Historical Society has a model which demonstrates the working of the vats. Otherwise, the saltworks have passed completely from the scene. It seems a shame.