A ruin more complete, it would be hard to realize. The vast structure of Roman civilization, built on the civilization of Greece and Assyria and Babylonia and Egypt, was hurled to the ground; and its fine and beautiful parts were scattered to the winds by barbarians who hated civilization because they were barbarians. The progress of science and literature and art stopped. The marvelous inventions of the past were forgotten and disused. A condition of semi-barbarism passed into Europe, and continued for a period of five hundred years, to which the name Dark Ages has been aptly given. A feeble light began to glow about 800 A. D. as a result of the activities of Charlemagne, but it almost expired when he did. It began again when the Crusaders came back from the Orient with knowledge of the civilization that still persisted there; and shortly after came the first effort of the Renaissance. Then followed the invention of the gun, and then the invention of printing:--and presto--the making of another Machine of Civilization is begun. Now let us realize three facts: one fact is that the Machine of Modern Civilization, though bigger and more complicated than the one of Trajan's time is not nearly so strong; another fact is that the Roman Machine was destroyed because it had become ineffective through carelessness and abuse; the third fact is that because in a measure, "history repeats itself," the Modern Machine may be destroyed, as the Roman was. The Machine of today is vastly weaker than Trajan's. Trajan's Machine was operated by a powerful empire that controlled the whole world absolutely. No rival of Rome existed. The structure of society was simple, homogeneous and strong. It was almost wholly military. It rested on force; but that force rested on reason, moderation, skill and patriotism. Rome had many foes; but they were so weak compared with Rome, that she had naught to fear from them--so long as she kept her Machine in order. The Machine of today is not only more complicated than that of Trajan, and therefore more liable to derangement from that cause alone--but it is supported by no government that dominates the world. On the contrary, the control is divided among a number of different nations that have diverse interests. The influence of this condition can be clearly seen in the fact that every great war has set back the progress of civilization for a while in all civilized countries, even though in some ways it has advanced it. The World War just finished, for instance, shook the very foundations of society; and we do not yet know that it did not impair them seriously. Certainly the Machine has not yet begun to run smoothly again. Certainly, the Bolsheviki are threatening it as seriously as the barbarians began to threaten Rome not long after Trajan's time. The Romans did not regard the barbarians then any more seriously than we regard the Bolsheviki now.