The Natural History of Coal. By E. A. Newell Arbor.
(Cam- bridge University Press, is. net.)—This volume, one of the "Cambridge Manuals of Science and Literature," goes thoroughly into its subject, and naturally includes much matter of a technical kind. Generally it shows that the subject is much more complex than is commonly thought. That coal is "buried sunshine," as some put it, is doubtless true; but the special forms on which the smishine acted are very various. As a rule, coal, when examined by the microscope, does not give enlightening results ; and we have to take many things into consideration when we would deter- mine its origin. A word may be said on a practical matter. "Peat," says Mr. Arber, "is expensive as a fuel." That is true, if we were to carry peat as we carry coal. Practically, when it has not to be carried, it is the cheapest of fuel. The village that is near to a peat bog gets its fuel much cheaper than that which is near to a coal pit.