Her hull was of a neutral color, and though the sun glanced from her metal flanks, a reflection from a convex side is not productive of a beam of light. It spreads according to the degree of convexity and is soon lost. What constitutes an apparent absence? The answer to that question is the example of a ship in space flight. The _Empress of Kolain_ did not radiate anything detectable in the electromagnetic scale from ultralong waves to ultrahigh frequencies; nothing at all that could be detected at any distance beyond a few thousand miles. The sweep of her meteor-spotting equipment would pass a spot in micro-seconds at a hundred miles; at the distance from the Relay Station, the sweep of the beam would be curved like the stream of water from a swung hose and therefore useless for direction finding, even though the Station's excellent equipment could pick up the signal. And so fleeting would be the touch of the spotting beam that the best equipment ever known or made would have no time to react, thus marking the signal. Theorists claim a thing nonexistent if it cannot be detected. The _Empress of Kolain_ was invisible. It was undetectable to radio waves. It was in space, so no physical wave could be transmitted to be depicted as sound. Its mass was inconsiderable. Its size was comparatively sub-microscopic, and therefore it would occult few, if any, stars. Therefore, to all intents and purposes, the _Empress of Kolain_ was nonexistent, and would remain in that state of material-non-being until it came to life again upon its landing at Venus. Yet the _Empress of Kolain_ existed in the minds of the men who were to find her. Like the shot unseen, fired from a distant cannon, the _Empress of Kolain_ was coming at them with ever-mounting velocity, its unseen course a theoretical curve. And the ship, like the projectile, would land if the men who knew of her failed in their purpose. Don Channing and Walt Franks found their man in the combined dining room and bar--the only one in many million miles. They surrounded him, ordered a sandwich and beer, and began to tell him their troubles. Charles Thomas listened for about three minutes. "Boy," he grinned, "being up in that shiny, plush-lined office has sure done plenty to your think-tank, Don." Channing stopped talking. "Proceed," he said. "In what way has my perspective been warped."