《天工开物·中篇·锤锻》
把铁逐节接合起来，要在接口处涂上黄泥，烧红后立即将它们锤合，这时泥渣就会全部飞掉。这里只是利用它的 气 来作为媒介。
凡铁性逐节粘合，涂上黄泥于接口之上，入火挥槌，泥滓成枵而去，取其神气为媒合。
When connecting iron sections, apply yellow mud to the joints, heat them until they are red-hot, and immediately hammer them together. At this time, the mud will fly off. The "air" here is only used as a medium.