At an ancient Chinese settlement straddling a river, scientists have uncovered what they regard as the earliest strong archaeological evidence of salt making, dating to 4,000 or so years ago.
This discovery highlights salt's central role in promoting the development of early states and empires, contend Rowan Flad of Harvard University and his colleagues. Large-scale salt production at critical locations in China led to extensive trading of the seasoning and of salted foods, they propose. Salt became crucial for provisioning armies of expanding Chinese states by 221 B.C., according to historical accounts.
In the Aug. 30 Proceedings of the National Academy of Sciences, Flad's group describes findings fr