Archive image from page 359 of De re metallica (1950). De re metallica deremetallica50agri Year: 1950 322 BOOK VIII. contains grains of it, are washed in frames or bowls ; the sands especially are also washed in troughs. More than one method is employed for washing on frames, for these frames either pass or retain the particles or concentrates of gold ; they pass them if they have holes, and retain them if they have no holes. But either the frame itself has holes, or a box is substituted for it; if the frame itself is perforated it passes the particles or concentrates of gold into a trough ;
Archive image from page 359 of De re metallica (1950). De re metallica deremetallica50agri Year: 1950 322 BOOK VIII. contains grains of it, are washed in frames or bowls ; the sands especially are also washed in troughs. More than one method is employed for washing on frames, for these frames either pass or retain the particles or concentrates of gold ; they pass them if they have holes, and retain them if they have no holes. But either the frame itself has holes, or a box is substituted for it; if the frame itself is perforated it passes the particles or concentrates of gold into a trough ; if the box has them, it passes the gold material into the long sluice. I will first speak of these two methods of washing. The frame is made of two planks joined together, and is twelve feet long and three feet wide, and is full of holes large enough for a pea to pass. To prevent the ore or sand with which the gold is mixed from falling out at the sides, small projecting edge-boards are fixed to it. This frame is set upon two stools, the first of which is higher than the second, in order that the gravel and small stones can roll down it. The washer throws the ore or sand into the head of the frame, which is higher, and opening the small launder, lets the water into it, and then agitates it with a wooden scrubber. In this way, the gravel and small stones roll down the frame on to the ground, while the A—Head of frame. B—Frame. C—Holes. D—Edge-boards. E—Stools F—Scrubber. G—Trough. H—Launder. I—Rowl.
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