Fuels

—artificial heat is commonly produced by combustion, caused by the chemical action of the oxygen of the air upon the hydrogen and carbon found in fuel. The different fuels in common use for cooking purposes are hard wood, soft wood, charcoal, anthracite coal, bituminous coal, coke, lignite, kerosene oil, gasoline, and gas. As to their respective values, much depends upon the purpose for which they are to be used. Wood charcoal produces a greater amount of heat than an equal weight of any other fuel. Soft wood burns quicker and gives a more intense heat than hard wood, and hence is best for a quick fire. Hard wood burns slowly, produces a larger mass of coals, and is best where long-continued heat is desired. Anthracite coal kindles slowly, and burns with little flame or smoke, but its vapor is sulphurous, and on that account it should never be burned in an open stove, nor in one with an imperfect draft. Its heat is steady and intense. Bituminous coal ignites readily, burns with considerable flame and smoke, and gives a much less intense heat than anthracite, lignite, or brown coal, is much less valuable as fuel. Coke is useful when a short, quick fire is needed. Kerosene and gas are convenient and economical fuels.