A number of the greatest public works ever conceived were motivated by the need to move salt. Salt has been in the forefront of the development of both chemistry and geology. Trade routes that have remained major thoroughfares were established, alliances built, empires secured, and revolutions provoked—all for something that fills the ocean, bubbles up from springs, forms crusts in lake beds, and thickly veins a large part of the earth’s rock fairly close to the surface.
