File:Tiangong Kaiwu Silver Smelting & Refining.jpg

The top illustration is of Ming Dynasty Chinese silversmiths smelting silver ore in a furnace, while the bottom illustration is of Chinese silversmiths carrying out the process of separating lead from the silver. Both illustrations were published in the Tiangong Kaiwu encyclopedia of 1637, written by the Ming Dynasty encyclopedist Song Yingxing (1587-1666). Both illustrations appear on pages 239 and 240 of E-tu Zen Sun and Shiou-Chuan Sun's English translation of the Tiangong Kaiwu (Pennsylvania State University Press, 1966).

The image is taken from

http://www.wiki.cn/wiki/%E7%81%B0%E5%90%B9%E6%B3%95