“The crater of Orizaba, which is much smaller than that of Popocatapetl, is still an awful chasm, and is probably not far from two miles in circumference. We could not take measurements of it, as all the instruments were down the mountain with the other party. It shows no signs of life, and with the exception of the heated sand on which we passed the night, we failed to notice any evidences of volcanic action still going on. But what a contrast this awful stillness to the great convulsions of which this mountain has once been the center. We had a magnificent view, for about an hour after sunrise, and as far as the eye could reach, peak after peak of lesser magnitude told the story of its volcanic birth. By a queer coincidence, I had brought _The Last Days of Pompeii_ with me to read in leisure moments, and as I looked out over the world at my feet, and thought of Bulwer’s vivid description of the last days of that doomed city, the thought suggested itself, ‘who knows how many Pompeiis are buried beneath these hoary hills, and what tales might these rocks repeat if they would?’” XVI. CORAL REEFS AND CAVES IN THE PACIFIC. THE ISLANDS OF THE PACIFIC—HOW THEY HAVE BEEN FORMED—WHAT THE CORAL IS—THE WONDROUS ARCHITECTS OF THE SEA—WHAT A UNITED STATES STEAMER SAW—HOW THE CORAL IS FISHED FOR—ROMANTIC STORY OF A CAVERN—HOW IT WAS DISCOVERED—AN ELOPEMENT AND EXERCISE IN DIVING—LOVE AND TURTLES—A BATTLE IN THE WATER—KILLED BY SHARKS—A MAIDEN’S GRIEF—THE PERIL OF A LOVER—SURPRISING A FATHER-IN-LAW—END OF A SUBMARINE COURTSHIP. The waters of the Pacific ocean contain thousands of islands far away from the coast. Their presence is recognized, long before they become visible, by clouds directly above them in the otherwise clear sky. The land absorbs the heat of the sun, and accumulates it faster than the water; soon an ascending current of warm air is formed, carrying up moisture into the colder regions of the atmosphere, where it is condensed and forms clouds. A similar phenomenon is observed in our western plains, where the sky is frequently clear enough in the morning, but by ten or eleven o’clock, enough heat has been accumulated to cause the formation of clouds. [Sidenote: THE ISLANDS OF THE PACIFIC.] The islands of the Pacific are of two kinds, called the higher and the lower. The lower rise but seven, ten, and rarely as high as one hundred feet above the level of the sea; while the higher islands reach an elevation of 10,000, 12,000, and even 15,000 feet. There is no transition between them. The most remarkable are the lower islands. Their appearance is very peculiar. In the first place, the eye is arrested by a white beach; then comes a line of verdure, due to tropical trees; then a lagoon of quiet water, of a whitish or a yellowish color, then another line of verdure, and finally, beyond all, the dark, blue waves of the ocean. Whitsuntide Island is a remarkable model of the structure of these islands: