destroyed all then known substances, from air to the most dense metals and stone. They settled down to the establishment of what became known as the Han dynasty in America, as a sort of province in their World Empire. Those were terrible days for the Americans. They were hunted like wild beasts. Only those survived who finally found refuge in mountains, canyons and forests. Government was at an end among them. Anarchy prevailed for several generations. Most would have been eager to submit to the Hans, even if it meant slavery. But the Hans did not want them, for they themselves had marvelous machinery and scientific process by which all difficult labor was accomplished. Ultimately they stopped their active search for, and annihilation of, the widely scattered groups of now savage Americans. So long as they remained hidden in their forests, and did not venture near the great cities the Hans had built, little attention was paid to them. Then began the building of the new American civilization. Families and individuals gathered together in clans or "gangs" for mutual protection. For nearly a century they lived a nomadic and primitive life, moving from place to place, in desperate fear of the casual and occasional Han air raids, and the terrible disintegrator ray. As the frequency of these raids decreased, they began to stay permanently in given localities, organizing upon lines which in many respects were similar to those of the military households of the Norman feudal barons, except that instead of gathering together in castles, their defense tactics necessitated a certain scattering of living quarters for families and individuals. They lived virtually in the open air, in the forests, in green tents, resorting to camouflage tactics that would conceal their presence from air observers. They dug underground factories and laboratories, that they might better be shielded from the electrical detectors of the Hans. They tapped the radio communication lines of the Hans, with crude instruments at first; better ones later on. They bent every effort toward the redevelopment of science. For many generations they labored as unseen, unknown scholars of the Hans, picking up their knowledge piecemeal, as fast as they were able to. During the earlier part of this period, there were many deadly wars fought between the various gangs, and occasional courageous but childishly futile attacks upon the Hans, followed by terribly punitive raids. But as knowledge progressed, the sense of