《天工开物·下篇·丹青》
其余的一般用墨，都是用松烟制成的，先使松树中的松脂流掉，然后砍伐。
其余寻常用墨，则先将松树流去胶香，然后伐木。
The other general types of ink are made from pine soot. First, the sap from the pine trees is drained, and then the trees are felled.