Charcoal
3 of the 7 encyclopedias on this shelf carry an entry for Charcoal. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a form of carbon obtained by burning vegetable or animal matter with a smothered fire. The bits of coal-black charred wood found in the ashes of a woodstove or a campfire are charcoal. When we say a lamp is smoking, it is producing charcoal. Stir up a fire so that no bits of wood are smothered in ashes, and we shall have no charcoal. Supply more air, or turn down the wick so that oil will not come too fast for the air, and the lamp will cease to smoke; that is it will stop producing charcoal. Wood-charcoal is hard and brittle and rings like a metal. It cannot be melted, nor dissolved in water. It burns without flame. It is not subject to decay. Many farmers char the lower ends of their fence posts to keep them from rotting off. Wood charcoal is one of the ingredients of gunpowder. It has the power of absorbing disagreeable odors and is used as a disinfectant. It makes an excellent powder for the teeth, and is much used in filters, as it allows the passage of water but arrests foreign substances. Wood charcoal is in demand for fuel, and for blacksmith fires. Without doubt, Longfellow's "Village Blacksmith" used charcoal. It is indispensable in smelting certain metals. Owing to its powers of absorption, it is sometimes given as a remedy. Charcoal crayons, obtained by charring splinters and twigs of willow, are used by artists in making sketches. Wood charcoal is produced in merchantable quantities by means of regular charcoal ovens, but the simplest and most widely used method is that of the charcoal burners. Split wood is stacked on end to form a round, pointed pile, like a cone or Indian's tepee. The pile is then banked or covered almost to the very tip with sods and earth or wet ashes to keep the air out. Holes are left here and there in the banking to admit some air. The wood is then fired at the very tip of the pile, and the fire is allowed to eat its way down the center and from the center toward the outside. The charcoal burner remains in constant attendance, but can tend a number of pits at the same time. He watches the issuing of the smoke with concern. As long as a thick, white smoke comes out, all is going right. If the smoke grows thin, or blue, the fire is burning too vigorously and is doing its work too well. He must close up some of the air vents or pile ashes on the peak to smother the fire. After he judges that the firing has proceeded long enough, several days perhaps, the burner closes up all the vents and the peak with ashes or earth, and leaves the pile to smolder and cool. Judgment and experience are needed to burn charcoal. If the air is shut out too closely the fire may go out, and then must be rebuilt. If the fire gets under headway for an hour the pit may burn out and the work of weeks be reduced to ashes. The whole secret of the process lies in the fact that, of the different elements that go to make up wood and oil, carbon is the last to take fire. The other elements fly into gas and are consumed before carbon is ignited at all. If a fire be smothered skillfully, so as to produce the right degree of heat and the right amount of combustion, the carbon is left behind as charcoal. Oak, ash, maple, beech, pine, elm, chestnut, and sycamore are largely used by the burners. A cord of wood burned skillfully yields about thirty bushels of charcoal weighing fifteen pounds to the bushel. Lampblack is a form of finely divided charcoal, obtained by catching the dense black smoke from half-smothered flames of oil lamps. The smoking lamps are placed in a specially constructed chamber beneath sacking on which the lampblack settles. Boneblack is made from fresh bones crushed into fragments, and subjected to the right degree of heat in earthenware retorts. Boneblack is used as a filter; liquids passing through it give up their color. See Gunpowder ; Carbon ; Diamond ; Coal
Collier's New Encyclopedia (1921)
an impure variety of carbon, prepared from vegetable substances or bones. Wood charcoal consists of wood burned with but little access of air. Billets of wood are built into a heap, which is covered with earth or sand. The heap is fired at openings left near the bottom of the pile, and the gases escape at small openings above. For making fine charcoal, such as that of willow, used in the manufacture of gunpowder, the wood is burned in iron cylinders or rather retorts, in which a process of destructive distillation removes the volatile hydrocarbons, pyroligneous acid, etc. By this more perfect means the process is accurately regulated. Charcoal is used in the arts as a fuel; a polishing powder; a table on ति. CASTLE OF CHAPULTEPEC which pieces of metal are secured in position to be soldered by the blowpipe; a filter; a defecator and decolorizer of solutions and water; an absorbent of gases and aqueous vapors; a nonconducting packing in ice-houses, safes, and refugerators; an ingredient in gunpowder and fire-works; in the galvanic battery and the electric light. Animal charcoal is used largely in sugar-refining, and as a disinfectant and filtering medium, is prepared by calcining bones in closed vessels. These are either retorts, similar to those in which coal is distilled for the production of illuminating gas, or they are earthenware pots, piled up in kilns and fired. Charges of 50 pounds of bones to a pot will require 16 hours of firing. The bones are then ground between fluted rollers, the dust removed, and the granulated material used for charging the filters of the sugar refiner. The material is used for removing color, feculencies, and fermenting ingredients from the syrup.
The Encyclopedia of Founding (1892)
Charcoal is what remains of wood after it has been exposed to a strong heat while protected from the access of the atmospheric air. Charred bituminous coal produces what is termed coke. See COKE.