QUOTE : In short, the period during which the main conditions of life for the vast majority of men have been subject to repeated and revolutionary changes had not even begun until the Renaissance and the great voyages, and did not assume anything like the accelerated pace which we now take for granted until well into the nineteenth century. Under these circumstances, there is no use in looking anywhere in earlier history for parallels to the successful inventions of the steam engine, the steamboat, the locomotive, the modern smelting of metals, the telegraph, the transoceanic cable, the introduction of electric power, dynamite and the modern high explosive missile, the airplane, the electric valve, and the atomic bomb. The inventions in metallurgy which heralded the origin of the Bronze Age are neither so concentrated in time nor so manifold as to offer a good counter-example.