Triumphs and wonders of the 19th century, a volume of original, historic and descriptive writings showing the many and marvellous achievements which distinguish an hundred years of material, intellectual, social and moral progress (1901)
Boyd, James Penny, 1836-1910 · Philadelphia, A. J. Holman & co · leaf 611
ese beams small platforms were nailed at distances equal to thelength of the stroke. The miner wishing to descend stepped upon the topplatform of one beam as it started on its down stroke. At the end of thisstroke he found himself twelve feet down the shaft, on a level with thesecond platform of… … INGERSoI.L-SEUGEANT DUPLEX STEAM-ACTUATED AIR COMPRESSOR. down stroke, he was conveyed to the bottom. By reversing the process hewas raised to the surface. In general, mining progress was slow up to the middle of the century.The production of the baser metals, here and abroad, increased…
Progress · Inventions
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