. De re metallica. Metallurgy; Mineral industries. 340 BOOK A—Launder. B—Interlacing fir twigs. C—Logs ; three on one side, for the FOURTH cannot BE SEEN BECAUSE THE DITCH IS SO FULL WITH MATERIAL NOW BEING WASHED. D—Logs at the head of the ditch. E—Barrow. F—Seven-proxged FORK. G—Hoe The third method of washing materials of this kind foUows. Two strakes are made, each of which is twelve feet long and a foot and a half wide and deep. A tank is set at their head, into which the water flows through a httle launder. A boy throws the ore into one strake ; if it is of poor quality he puts in
. De re metallica. Metallurgy; Mineral industries. 340 BOOK A—Launder. B—Interlacing fir twigs. C—Logs ; three on one side, for the FOURTH cannot BE SEEN BECAUSE THE DITCH IS SO FULL WITH MATERIAL NOW BEING WASHED. D—Logs at the head of the ditch. E—Barrow. F—Seven-proxged FORK. G—Hoe The third method of washing materials of this kind foUows. Two strakes are made, each of which is twelve feet long and a foot and a half wide and deep. A tank is set at their head, into which the water flows through a httle launder. A boy throws the ore into one strake ; if it is of poor quality he puts in a large amount of it, if it is rich he puts in less. The water is let in by removing the plug, the ore is stirred with a wooden shovel, and in this way the tin-stone, mixed with the heavier material, settles in the bottom of the strake, and the water carries the light material into the launder, through which it flows on to a canvas strake. The very fine tin- stone, carried by the water, settles on to the canvas and is cleansed. A low cross-board is placed in the strake near the head, in order that the largest sized tin-stone may settle there. As soon as the strake is filled with the material which has been washed, he closes the mouth of the tank and continues washing in the other strake, and then the plug is withdrawn and the water and tin-stone flow down into a tank below. Then he pounds the sides. 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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Keywords: ., bookauthoragricolageorg14941555, bookcentury1900, booksubjectmin
