. De re metallica. Metallurgy; Mineral industries. BOOK A—Large bowl D—Other large bowl which coiners Small bowl. it. This bowl, when shaken, is held in one hand and thumped with the other hand. In other respects this method of washing does not differ from the last. I have spoken of the various methods of washing sand which contains grains of gold ; I will now speak of the methods of washing the material in which are mixed the small black stones from which tin is made^". Eight such methods are in use, and of these two have been invented lately. Such metalliferous material is usuall
. De re metallica. Metallurgy; Mineral industries. BOOK A—Large bowl D—Other large bowl which coiners Small bowl. it. This bowl, when shaken, is held in one hand and thumped with the other hand. In other respects this method of washing does not differ from the last. I have spoken of the various methods of washing sand which contains grains of gold ; I will now speak of the methods of washing the material in which are mixed the small black stones from which tin is made^". Eight such methods are in use, and of these two have been invented lately. Such metalliferous material is usually found torn away from veins and stringers and scattered far and wide by the impetus of water, although sometimes venae dilatatae are composed of it. The miners dig out the latter material with a broad mattock, while they dig the former with a pick. But they dig out the little stones, which are not rare in this kind of ore, with an instrument like the bill of a duck. In districts which contain this material, if there is an abundant supply of water, and if there are valleys or gentle slopes and hollows, so that rivers can be diverted into them, the washers in summer- ^"As the concentration of crushed tin ore has been exhaustively treated of already, the descriptions from here on probably refer entirely to alluvial Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Agricola, Georg, 1494-1555; Hoover, Herbert, 1874-1964. New York, Dover Publications
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