Excerpt from The Natural History of CoalIn the past it would seem that the root of Our difficulties in regard to agreement on such points has been the initial hypothesis, that all coals, or at least all the coals of the Carboniferous period, were derived from the same type of mother substance, accumulated under the same conditions, and converted by the same means. It is quite clear that such an assumption is entirely false. There was no one original mother substance, no one original mode of accumulation, and, if all the substances popularly termed coals, whatever their geological age may be, are taken into considera tion, no one mode of conversion. Modern research, as we shall see in the chapters which follow, has shown that each case, each seam of coal, must be examined, studied, and judged entirely on its own merits. When this fact has become more widely recognised, it would seem likely that our knowledge of the natural history of coal will progress more rapidly than in the past.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.