Rivers a universal problem--Character of the Mississippi--Failure of the levee system--The building of levees--Three great sections--Damage of overflows--Fighting for the levee--Storm on the river--Scene at a crevasse--The flood in the rural districts--In the city--Closing a crevasse--Refugees on the levee--Crooked streams 261 CHAPTER XV. THE FLOOD OF 1890. Floods of other years--Warning of the Signal Service--The water rising--At Greenville, Mississippi--The fight for the Morganza line--The waters win--Other crevasses--Extent of the damage--Objections to levees--Levees versus outlets--Terrible floods in China--A proposed outlet--Reflection on present policy 296 CHAPTER XVI. THE JOHNSTOWN FLOOD. The dam system of India--American “cheap goods and haste"--The Little Conemaugh Valley--Heavy rains--Johnstown flooded--The artificial lake--A poor dam--No uneasiness--How the water would move--The dam breaks--Terrible rush of the flood--An engine chased--A warning whistle--Locomotives hurled about like toys--Flying for life--Escapes and losses 324 CHAPTER XVII. INCIDENTS AT JOHNSTOWN. Suddenness of the flood--It divides--A chaotic scene--Fire breaks out--Faith of the perishing--Narratives: the Hulbert House; Rev. D. M. Miller’s story; Mr. Calliver’s escape; Dr. Beale and family--Morning: the stricken multitude; Mr. Rose’s narrative; Talmage’s letter; the grief of the survivors 343 CHAPTER XVIII. RELIEF MEASURES. The people in want--Johnstown after the flood--Human ghouls--Relic hunters--Temporary government--A dictatorship--Hospitals and morgues--Prompt response of the public--Aid from various cities--Losses by the flood 367 CHAPTER XIX. FAMINE AND PESTILENCE. Signs and omens--Natural causes--Bengal famine of 1866--Relief Measures--Results--Pestilence and contagion--Black death--Its frequent ravages--Fright--A romance of Florence 384 CHAPTER XX. THE VOLCANO. Erroneous views--Myths--Active principle in volcanoes--Atmospheric pressure--Rain at eruptions--Lava, pumice, ashes and tufa--Different phases of action--Stromboli, the “lighthouse"--Lava bubbles--Thrilling adventure--Lost!--Theory of a molten earth--Objections to it--The earth cools slowly--Subsidence and chemical action--Distribution of volcanoes--Their work and forms 394 CHAPTER XXI. GREAT ERUPTIONS OF VESUVIUS. Pompeii long buried--Excavations begun--A hermetically sealed city--Scenes in the town--Pliny’s story--Hundreds stifled--Finding the bodies--Subsequent eruptions--Notable convulsion of 1538--The eruption of 1531, 1737 and 1793--Recent observations 421 CHAPTER XXII. OTHER GREAT ERUPTIONS.