He gathered a whole sackful, but it yielded only enough indigo to dye a handkerchief. Wang was well aware that in fact artificial indigo became commercially available as long ago as 1897, having been synthesized by German chemists. Synthetic indigo has exactly the same chemical composition as natural indigo, and it is of high purity, easily available, and convenient to use.
他知道其實一八九七年德國合成靛藍就已問世，成分與植物藍一模一樣，而且純度高、原料供應充足、使用方便。