Bulletin . Twtoother openings (h and t) into the top and bottom of / are for theintroduction of the gas flame or other source of ignition. The operation is carried out in the following way: A weighedquantity of dust is placed in front of n, in the glass tube m. The airin the bottle a is compressed to the desired pressure by means of thefoot bellows connected to b. After placing the gas jet (q) in positionthe stopcock p is quickly opened. The outrush of air from e blowsthe dust into the air and carries it to the source of ignition, where thebehavior of the dust is observed through the windows.
Bulletin . Twtoother openings (h and t) into the top and bottom of / are for theintroduction of the gas flame or other source of ignition. The operation is carried out in the following way: A weighedquantity of dust is placed in front of n, in the glass tube m. The airin the bottle a is compressed to the desired pressure by means of thefoot bellows connected to b. After placing the gas jet (q) in positionthe stopcock p is quickly opened. The outrush of air from e blowsthe dust into the air and carries it to the source of ignition, where thebehavior of the dust is observed through the windows. The firstseries of experiments was made on finely ground samples of sources of ignition used were an electric spark, electrically heatedplatinum wTire, and a small gas flame. The second series of experi-ments was a study of finely ground dust of each of the followingmaterials: Brown coal, bituminous coal, dant (slack), charcoal, wheatflour, wood sawdust, lycopodium powder, metallic aluminum, and. Figure 10.—First coal-dust ignition apparatus of Bedson and Widdas. a Trans. Inst. Min. Eng., vol. 32, 1907, p. 529. 134 THE EXPLOSIBILITY OF COAL DUST. metallic magnesium. The source of ignition used in each case was asmall gas flame, the amount of dust 1 gram. In every materialexcept dant and charcoal inflammation took place. In a second papera the same authors record the results of furtherexperiments on coal dust with apparatus (fig. 11), somewhat differentfrom that described above. In order to secure better control of theconditions of ignition they substituted a coil of platinum wire for thegas flame and electric spark used in some of their earlier could in this way obtain a considerable range of temperature,and could measure approximately the temperature of the coil duringany experiment by measuring the current passing through the is given the current that was found necessary to produceinflammation of each of the dusts named: Current requi
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
