"Sleep. And when you awake everything you know of the twentieth century will be gone from your mind. Tonight is January 21, 1882. There are no such things as automobiles, no planes, computers, television. 'Nuclear' appears in no dictionary. You have never heard the name Richard Nixon." <P> Did illustrator Si Morley really step out of his twentieth-century apartment one night -- right into the winter of 1882? The U.S. Government believed it, especially when Si returned with a portfolio of brand-new sketches and tintype photos of a world that no longer existed -- or did it?