Turf or peat has been charred lately in France, it is said, by a peculiar process, and, according to the account given in Sonnini's Journal, is superior to wood for this purpose. Charcoal of turf kindles slower than that of wood, but emits more flame, and burns longer. It boiled a given quantity of water four times, while an equal weight of wood charcoal boiled the same quantity but once. In a goldsmith's furnace, it fused eleven ounces of gold in eight minutes, while wood charcoal required sixteen. The malleability of the gold, too, was preserved in the former instance, but not in the latter. Iron heated red-hot by it, in a forge, was rendered more malleable. In charring wood it has been conjectured, that a portion of it is sometimes converted into a pyrophorus, and that the explosions that happen in powder-mills are sometimes owing to this. Bartholdi supposes, that such explosions are owing to the formation of phosphoretted hydrogen gas, while others attribute them to the absorption of oxygen, by the hydrogen contained in the coal, and the consequent evolution of free caloric. Percussion, which necessarily takes place in mixing the materials of gunpowder by stampers, no doubt accelerates the combustion. The addition of water, and having the charcoal previously pulverized, will prevent such accidents. (See _Gunpowder_.) Coal prepared in the manner above stated, is liable to many foreign admixtures, nor can the process be so well regulated as to produce coal of a uniform quality throughout. The present improved process has many advantages, as experience has proved. It consists in charring the wood in confined vessels, made of iron. These are usually cylindrical, furnished with an iron cover, and placed in furnaces. The pyroacetic, formerly called the pyroligneous, acid, which is formed in the destructive distillation of wood, is caught for use. This acid is useful to the calico printer, dyer, &c. in making their iron liquor, and when purified, is employed in Europe in the place of vinegar, as it is more pungent, and highly concentrated. When pine and various kinds of wood, which yield turpentine, are carbonized, we obtain tar during the process. Chaptal informs us, that tar is obtained from the wood of the trunk, branches, and roots of the pine, which are heaped together, covered with turf, and set on fire to produce a close combustion, in the same manner as for making charcoal. The oily parts which are disengaged, trickle down, and are received in a gutter, which serves to convey them to a tub. The most fluid part is sold under the name of huile de cade; and the thicker part is the tar used for paying or painting the parts of shipping and other vessels.