| 释义 | mc·dou·gall furnace \mə̇kˈdügəl-\ noun
 Usage: usually capitalized M&D
 Etymology: after McDougall, 19th century British engineer
 : a roasting furnace consisting of a vertical cylindrical shaft containing several superposed hearths over which ore entering at the top is made to pass consecutively by mechanical rabbles rotating around a central shaft
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