But he has not been satisfied with relying wholly upon his own observations and world-studies. No man, however active and industrious, can collate and digest all the interesting information which may cluster about any important subject. The average life is too short for the performance of such exhaustive study. The author has therefore consulted many works upon mining and kindred subjects, adding their funds of knowledge to his own researches, in order, so far forth as possible, to perfect his work. Besides, he is specially indebted to Professor Simonin, author of _La Vie Souterraine_, and has relied upon him for many facts and figures, particularly in regard to the coal mines of France and other countries. Many individuals, professionally conversant with the subjects discoursed of, have also been personally consulted in various countries; while several literary gentlemen of eminence have kindly lent the author their aid. Among the latter it is permissible to mention Mr. Junius Henri Browne, of New York, and the late Col. Albert S. Evans, of San Francisco. In preparing the matter for the press, it has been found convenient to make use of words borrowed from the French and other languages, and also of terms more or less technical in their character. They are not numerous, and are so well understood either by context or by popular use that a glossary is not considered necessary. The author takes this opportunity to thank the newspaper press and the public for the generous reception accorded to his previous publications, hoping, in the language of the business card of the times, to merit a continuance of the same. T. W. K. CONTENTS. I. BELOW THE SURFACE. DIFFUSION OF KNOWLEDGE.—WHAT THE WORLD BELIEVES.—MUNGO PARK IN AFRICA.—WHY THE NATIVES PITIED HIM.—EXTENT OF UNDERGROUND LIFE.—DISTRIBUTION OF THE EARTH’S WEALTH.—VALUE OF MINES.—THEIR EXTENT AND IMPORTANCE.—COAL AND IRON.—MYSTERIES OF MINES.—EXPERIENCE WITH A NOVICE.—CHANGES OF SEASONS TO A MINER.—DANGERS IN MINES.—LIFE IN CAVERNS.—UNDERGROUND IN METAPHOR.—SOCIAL MINING.—OBJECT OF THIS VOLUME. Page 27 II. DISCOVERY OF COAL. SAVAGE THEORIES ABOUT COAL.—EXPERIENCE OF A SIBERIAN EXPLORING PARTY.—BURNING BLACK STONES.—MINERAL FUEL AMONG THE ANCIENTS.—THEIR MOTIVE POWER.—CHINESE TRADITIONS.—CHINESE GAS WELLS.—HISTORY OF COAL IN ENGLAND.—A ROYAL EDICT.—CURIOUS STORY OF THE MINER OF PLENEVAUX.—EXTENT OF COAL FIELDS THROUGHOUT THE GLOBE.—THE QUAKER AND THE YANKEE PEDLER.—THE FIRST ANTHRACITE.—BELLINGHAM BAY AND THE CHINOOKS.—HOW COAL WAS FORMED.—INTERVIEWING A REPTILE.—THEORIES OF THE ANCIENTS.—RIVERS OF OIL OF VITRIOL.—ANCIENT AND MODERN FIRE WORSHIPPERS. 37 III. BORINGS AND SHAFTS.