XIII. THE CONQUEST OF THE ETHER--MOVING PICTURES--RISE OF JAPAN AND THE UNITED STATES 301 XIV. THE FRUITION OF INVENTION 322 XV. THE MACHINE OF CIVILIZATION, AND THE DANGEROUS IGNORANCE CONCERNING IT, SHOWN BY STATESMEN 333 XVI. THE FUTURE 341 LIST OF ILLUSTRATIONS PAGE Carvings in Ivory and in Stone of Cavern Walls made by the Hunters of the Middle Stone Age 3 Early Babylonian Signs, Showing Their Pictorial Origin 27 Villa of an Egyptian Noble 34 The Pyramids of Gizeh 36 Assyrians Flaying Prisoners Alive 44 Two Cretan Vases 52 Insurgent Captives Brought Before Darius 58 The Lighthouse of the Harbor of Alexandria in the Hellenistic Age 77 Triumphal Procession from the Arch of Titus 96 The Printing of Books 113 Portuguese Voyages and Possessions 126 Hero's Engines 150 Hero's Altar Engine 151 Leupold's Engine 154 INVENTION, THE MASTER-KEY TO PROGRESS INVENTION, THE MASTER-KEY TO PROGRESS CHAPTER I INVENTION IN PRIMEVAL TIMES Our original ancestors dwelt in caves and wildernesses; had no sewed or fabricated clothing of any kind; subsisted on roots and nuts and berries; possessed no arts of any sort; were ignorant to a degree that we cannot imagine, and were little above the brutes in their mode of living. Today, a considerable fraction of the people who dwell upon the earth enjoy a civilization so fine that it seems to have no connection with the brutish conditions of primeval life. Yet, as these pages show, a perfectly plain series of inventions can be seen, starting from the old conditions and building up the new. The progress of man during the countless ages of prehistoric times is hidden from our knowledge, except in so far as it has been revealed to us by ruins of ancient cities, by prehistoric utensils of many kinds, and by inscriptions carved on monuments and tablets. The sharp dividing line between prehistoric times and historic times, seems to be that made by the art of writing; for this epochal invention rendered possible the recording of events, and the consequent beginning of history.