Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/34

24 of fire, is rendered probable, as much by these trials as by the geological observations above mentioned. The conversion of bituminized wood into true coal may possibly be the effect of a consolidation produced by the agency of fire, but I shall leave this argument in the hands of those who have undertaken the defence of this theory—having entered into this train of reasoning, not by design, but from the unavoidable concatenation of experiments.

A circumstance occurred in the coaly residuum of the wood tar which it is worth while to notice, although of an accidental nature, and not essentially affecting the history of the vegetable bitumen or pitch which I have described. It bore no resemblance to common charcoal, but was more like black lead. It was as glossy, and although not so soft, marked paper with a similar streak. It was inflated, and therefore minutely scaly, and porous, and was attracted by the magnet. Muriatic acid took up a portion of iron from it, as it does from many varieties of plumbago, and the remainder resembled plumbago after it had been submitted to the action of acids.