PREFACE. IN the following pages an endeavour is made to delineate the principal features in the growth of the great coal industry, with special reference to improvements in engineering, by means of which it has become possible for the miners to open out their deep "subterranean cities" and to procure and bring to the surface the vast quantities of coal which are now annually drawn from the mines of this country. Apart from the value of coal as the mainspring of the great industrial pre-eminence of the kingdom, it is hoped that the narrative may not be without interest of another kind, inasmuch as it furnishes an account of the origin of some of the most |