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 and especially from trees which have been topped : for these contain in the right proportion the qualities of closeness admixture of mineral matter and moisture. Again better charcoal comes from trees in a sunny dry position with a north aspect than from those grown in a shady damp position facing south. Or, if the wood used contains a good deal of moisture, it should be of close texture; for such wood contains more sap. And, for the same reason, that which is of closer texture either from its own natural character or because it was grown in a drier spot, is, whatever the kind of tree, better. But different kinds of charcoal are used for different purposes: for some uses men require it to be soft; thus in iron-mines they use that which is made of sweet chestnut when the iron has been already smelted, and in silver-mines they use charcoal of pine-wood: and these kinds are also used by the crafts. Smiths require charcoal of fir rather than of oak: it is indeed not so strong, but it blows up better into a flame, as it is less apt to smoulder: and the flame from these woods is fiercer. In general the flame is fiercer not only from these but from any wood which is of open texture and light, or which is dry: while that from wood which is of close texture or green is more sluggish and dull. The fiercest flame of all is given by brushwood; but charcoal cannot be made from it at all, since it has not the necessary substance.

They cut and require for the charcoal-heap straight