activated carbon africa animal animal glue anthracite ash back-formation bamboo charcoal barbecue biochar blacksmith blast furnace bloomery bone char borax briquette bus bushel by-product camping carbon carbon monoxide carbonization cast iron catoctin mountain park central europe charcoal biscuit charring clay coal combustion copper crayon deforestation drawing employment england english language finery forge finland fixative flue fossil fuel fuel garden gas mask gelatin grill gunpowder hardwood henry ford horticulture hydrocarbon industrial revolution intestine iron japan laboratory limestone magnesium metallurgy north korea odor oil oxygen painting paraffin pencil pine pre-columbian pyroligneous acid pyrolysis research retort sawdust scandinavia shem slash-and-char smelting sodium nitrate soil starch stomach sugar syrup tang zhongming tar temperature terra preta tilia toxin united states vegetation volume weight willow wood wood gas wood gas generator world war ii