VI. VESUVIUS IN ERUPTION AT NIGHT 66 VII. THE GEYSERS OF ICELAND 78 VIII. ISLAND OF STAFFA 93 IX. FINGAL'S CAVE 97 X. FORUM OF POMPEII 131 XI. GREAT FALL OF NIAGARA 135 XII. ESCAPE ON THE ICE 157 XIII. THE WATER-SPOUT 194 XIV. ACTINIÆ--CORAL BUILDERS 206 XV. SEPIAS 231 XVI. NAUTILUS 239 XVII. AURORA BOREALIS (FRONTISPIECE.) XVIII. SPECTRE OF THE BROCKEN 285 XIX. DOVER CASTLE 293 XX. FATA MORGANA 299 WONDERS OF THE EARTH, SEA, AND SKY. PART I. WONDERS OF THE EARTH. CHAPTER I. PARLEY EXPLAINS HOW THE STRATA OF THE EARTH ARE PLACED. I am now going to tell you, my young friends, about some of the wonderful things in the earth, sea, and sky. A great number of them I have seen myself in my travels through various countries, and others I have only read of; but I shall tell you nothing that is not strictly true, for I do not wish so much to astonish you as to make you take pleasure in contemplating the works of God, and to increase your knowledge of His goodness, wisdom, and power. I shall begin with some of the wonders of the earth which, as I suppose you know, belong to the branch of natural history which is called geology; and to enable you to understand what follows, I must first explain how the materials which compose the ground you tread upon are arranged. If you hastily travel over any extensive tract of country, such as that between New York and Philadelphia, or between London and Bristol, you might think that all the different substances, clay, chalk, limestone, and granite, were irregularly mixed together. This is, however, not the case, when taken on a great scale; for if you more carefully examine, you will find that the various sorts of earth are disposed in layers, or _strata_, and that a uniform order of arrangement is nearly preserved.