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 616
servoir, from which it is piped to themachine which it is to run. One of the advantages of air-driven machines under ground is that theexhaust furnishes fresh air to the miners and cools the atmosphere. Theresult has been that in metal mines, where there are no noxious gasesescaping from the… … INGERSOLL-SERGEANT DUPLEX STEAM-DRIVEN AIR COMPRESSOR. that, even with the safety-lamp, gas would be exploded if a large amount ofit had accumulated, more attention was paid to ventilation. Levels andshafts were divided to produce a natural current; the size of the drifts wascarefully figured in…
Progress · Inventions
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