《水经注·卷三十三》
溪流所经的山峡旁有盐井三口，相距各数十步，用直径五尺的大木桶来装，不停地煮盐。
溪硖侧，盐井三口，相去各数十步，以木为桶，径五尺，修煮不绝。
Along the canyon where the stream flows, there are three salt wells, each dozens of steps apart, and they are filled with 5-foot-diameter wooden barrels for non-stop salt boiling.