Salt was vital to the Cape's large fishing fleet and maritime trade. Most Cape salt was obtained by importation and boiling of seawater using prodigious amounts of scarce wood. With imports shut off by the Revolutionary War, John Sears, a Quivet Neck resident, began experimenting in 1776 with evaporative precipitation of sea water, an effort which resulted in only 8 bushels of salt after weeks of effort. Inventing portable roofs to cover the salt vats, protecting them from rain, Capt. Sears obtained a patent in 1799.

By 1832, 881 salt works produced some 250,000 bushels of salt annually. With the discovery of salt in mines in New York, and the advent of the railroad, the evaporative process was far too expensive, and the business declined. The last salt vats were dismantled in the 1890s.

A plaque commemorates this industry.