When coal is employed in fire-works, it is to be pulverized, and sifted in the usual way. For some purposes it is preferred to charcoal, in consequence of the bitumen it contains, which appears to contribute to the rapidity of the combustion. It is to be observed, that, as the base of coal is carbon, its action is the same as charcoal, and therefore, by producing the same effects, or nearly so, as charcoal itself, the phenomena it presents are analogous. As 12.709 parts of carbon, according to Kirwan, are required to decompose 100 parts of nitrate of potassa, we may readily ascertain the quantity of real carbon in any specimen of coal. According to Kirwan, 50 grains of Kilkenny coal will decompose 480 grains of nitrate of potassa, from which it is inferred, that ten grains would have decomposed 96 of nitrate of potassa, precisely the same quantity of charcoal, which would have produced the same effect. Therefore, Kilkenny coal is composed almost entirely of carbon. Cannel coal, when treated in the same manner with nitrate of potassa, left a residuum of 3.12 in the hundred parts of earthy ashes; and 66.5 of it were required to decompose 480 grains of nitrate of potassa, but 50 of charcoal would have been sufficient. From this experiment, it appears, that 66.5 grains of cannel coal contain 50 grains of charcoal, and 2.08 of earth; the remaining 14.42 grains must be bitumen. In a similar manner, by knowing the quantity of coal required to decompose a given quantity of nitrate of potassa, when melted in a crucible, the quantity of carbon in any variety of this substance may be ascertained. With respect to the earthy and metallic ingredients of coal, we may ascertain them by burning the coal, with free access of air. What remains unburnt must be considered an impurity. Its weight may be ascertained, and its nature by analysis. As the object, however, is generally to determine the relative proportion of combustible matter, or carbon, which different species of coal are capable of yielding, that point may be determined in the manner already stated. That coal originates from vegetables, whatever opinion may be formed to the contrary, we may fairly infer from a variety of vegetable remains, and impressions of animals that are both found in the strata of coal, and in earthy strata above and below them. Of its submarine origin, there can also be no doubt; or why do we find in it shells, the impression of fish, and other productions of the ocean? That coals _grow like vegetables_, an opinion with the uninformed, is contrary to fact, and the nature of things. We may notice, in this place, another substance which sometimes is found partially carbonized; we mean turf.