Terrestrial heartlands had to find another source of salt. Riddled with mines and tunnels, the Alps produced rock salt for the areas to the north. From the seventeenth century onwards, England extracted salt from the Cheshire mines. As a result, whole areas of Cheshire subsided, turned into swamp and vanished like the Cheshire Cat’s smile. The Middle East and Persia obtained salt from salt lakes, the remains of ancient seas. Relatively cheap to produce, salt was a heavy commodity, and in large countries such as France and Russia the salt trade remained local. Nationwide salt markets did not develop there until the coming of the railways, as was also the case with grain, firewood and building materials.
Cardinal Richelieu said that the salt tax was as important for France as the silver mines were for Spain. In Brittany, where salt was obtained in coastal ponds, it was cheap; but there was no salt in the interior of the country. The kingdom divided its own territory into six regions, imposing different levels of salt tax,
Sugar cane grows only in the tropics and needs plenty of soil, sun and water. This tall, robust plant is a very efficient photosynthesiser. In the right conditions it produces a large biomass – 20 kilograms per square metre. But it quickly exhausts even the most fertile soil. Producing sugar on colonial plantations was all about timing. Sugar cane had to be planted at exactly the right time of the year. It grows for a year or more and can reach twice the height of a man. It had to be cut before it flowered, because when the plant matured the sap lost part of its sugar content. Then the cane had to be processed immediately to prevent the sap spoiling. One slave gang chopped the stalks with a machete or crushed them in a mill. Then another gang boiled the sap in vats heated by cane waste which had been dried in the sun. This process caused sugar to crystallise, so that yet another gang could separate the crystals from the molasses. One team cleaned and packed sugar, while another distilled molasses into rum. The whole process was very labour-intensive but endlessly repetitive, which meant the work could be carried out by slaves and later by machines. Free labour was no match for slave gangs when it came to mass-scale, tropical commodities such as sugar or cotton. The size of the plantation was also crucial: the rapid processing of the cane required many pairs of hands at once, and small farms couldn’t compete.
Originating in New Guinea, sugar cane was brought to India around 500 ce , and the method of boiling the sap was invented there. Caravans brought it to Europe by the Silk Road from Persia, together with silk and pearls. The first mention of sugar in Venice occurred in 996; before that the only form of sweetener was honey. In the Middle Ages sugarloaves were worth their weight in gold, and statuettes were carved from them as if from marble. Sugar was taken as a medicine; cookery books suggested adding a pinch of sugar to meat and fish as a precious spice.
Columbus’s father-in-law was a sugar planter from Madeira, and on his second voyage Columbus took sugar cane to the island of Saint-Domingue, now Haiti. At first, the Spaniards forced the natives to work the cane, but they died out, so from 1509 the planters started buying African slaves. The Portuguese planted sugar cane in Brazil; for a while, they produced most of the sugar for European consumption. Sugar plantations fed triangular trade: Africa supplied labour and America provided land, while Europe consumed sugar, paying for it with industrial goods.