Coarse Sea Salt from Clay Brine-Pits in the Sun, Ure 1839

In warm countries the sun alone makes salt from the sea. Andrew Ure (1839): dig shallow pits with smooth clay bottoms by the shore, let sea water settle in a deeper reservoir, then lead it slowly through the pits. When the brine turns reddish, salt crystals form and sink; rake them out and leave them on the banks to drain and dry. The picture: raking salt in the brine-pits at Marakkanam, India.