. De re metallica. Metallurgy; Mineral industries. BOOK VIII. 321 concentrates are washed separately in different bowls from those which have settled on the canvas. This bowl is smooth and two digits wide and deep, being in shape very similar to a small boat; it is broad in the fore part, narrow in the back, and in the middle of it there is a cross groove, in which the particles of pure gold or silver settle, while the grains of sand, since they are lighter, flow out of it. In some parts of Moravia, gold ore, which consists of quartz mixed with gold, is placed under the stamps and crushed wet.
. De re metallica. Metallurgy; Mineral industries. BOOK VIII. 321 concentrates are washed separately in different bowls from those which have settled on the canvas. This bowl is smooth and two digits wide and deep, being in shape very similar to a small boat; it is broad in the fore part, narrow in the back, and in the middle of it there is a cross groove, in which the particles of pure gold or silver settle, while the grains of sand, since they are lighter, flow out of it. In some parts of Moravia, gold ore, which consists of quartz mixed with gold, is placed under the stamps and crushed wet. When crushed fine it flows out through a launder into a trough, is there stirred by a wooden scrubber, and the minute particles of gold which settle in the upper end of the trough are washed in a black A—Stamps. B—Mortar. C—Plates full of holes. D—Transverse launder. E—Planks full of cup-like depressions. F—Spout. G—Bowl into which the concentrates fall. H—Canvas strake. I—Bowls shaped like a small boat. K—Settling-pit under the canvas strake. So far I have spoken of machines which crush wet ore with iron-shod stamps. I will now explain the methods of washing which are in a measure peculiar to the ore of certain metals, beginning with gold. The ore which contains particles of this metal, and the sand of streams arid rivers which. 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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