Of the former methods, when gold was found loose in sand or gravel, washing was the earliest and most universally practised, and was called panning. 威廉·亨利·杜利特.世纪发明.
The reports stated that the Mexicans had been panning gold for a hundred years out of these deposits. 弗兰克·刘易斯·戴尔.爱迪生的生平和发明.