. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . Fig Bnintons automatic sampler. ORE SAMPLING. 601 mi^ht result from isochronal motion. Experience has shown that 10 per cent of 20 or 2 per cent, of the original amount of ore, is usually quite sufficient for the finalsample, though in exceptional cases 15 percent, of 80 per cent., or 4^ per cent, of the whole,are taken. Careful tests of this machine in resampling lots of ore have shown a limit oferror of
. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . Fig Bnintons automatic sampler. ORE SAMPLING. 601 mi^ht result from isochronal motion. Experience has shown that 10 per cent of 20 or 2 per cent, of the original amount of ore, is usually quite sufficient for the finalsample, though in exceptional cases 15 percent, of 80 per cent., or 4^ per cent, of the whole,are taken. Careful tests of this machine in resampling lots of ore have shown a limit oferror of less than one-fourth of 1 per cent. For further details see Trans. Am. vol. xiii. p. 639. Another device to facilitate sampling is the split shove!, which is an ordinary shovel sodivided that in being pushed through a lot of finely crushed ore, a certain proportion only,sav one fourth, is taken. Bruntons shovel, Fig. 2, is one of the best of these. This tool,which is described in the and Mining Journal, ]. li. 71><, consists essentiallyof a fiat-bottomed, well-balanced steel shovel, 10 in. in width, having vertical sides, and two. Fig. 2 —Bruntons sampling shovel. central partitions. 2\ in. apart, thus dividing the shovel into three compartments, the centerone being closed by a curved back, and having a width one-quarter of the whole. The oper-ator pushes the shovel into a pile of fineiy crushed ore. As he raises the shovel, it is drawnback with a sjiarp rotary motion to the Ilght, which throws the ore contained in the outsidecompartments out from the back end of the shovel into a rejected ore pile. When the nec-essary throw to accomplish this result has been given, the motion is reversed, and the shovelbrought rajiidly to the left, which action discharges the sample from the central compart-ment of the shovel upon another pile. While the required motions are somewhat difficult, and beginners are awkward at first, afew weeks practice
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