《天工开物·中篇·锤锻》
由炉甘石升炼而成的黄铜，熔化后要趁热敲打。如果是其中加入锌而锤炼成的，则要在熔化后经过冷锤。
凡黄铜，原从炉甘石升者不退火性受锤；从倭铅升者出炉退火性，以受冷锤。
The yellow copper smelted from calamine needs to be forged while it is hot after melting. If zinc is added and forged, cold forging is required after melting.