《天工开物·上篇·作咸》
盐的种类很多。大体上可以分为海盐、池盐、井盐、土盐、崖盐和砂石盐等六种，但是东部少数民族地区出产的树叶盐和西部少数民族地区出产的光明盐还不包括在其中。
凡盐产最不一，海、池、井、土、崖、砂石，略分六种，而东夷树叶，西戎光明不与焉。
There are many types of salt. Generally, they can be divided into six types: sea salt, pond salt, well salt, earth salt, cliff salt, and sandstone salt. However, the leaf salt produced in the eastern minority areas and the light salt produced in the western minority areas are not included.