The Big Front Yard and Other Stories by Clifford D. Simak

brushed along and blurred the surface. It moved in short and flowing motions, and when it stopped its motion it became a part of the surface, blending into it.
    It was watching him, he knew, looking him over, although what there was to see of him he could not imagine. Sensitive, perhaps, to another personality, to another thing that shared with it that strange and undefinable quality which made up life. A force field, he wondered – was that what he was, a disembodied intelligence carried in a force field?
    He stayed still so the thing could look him over. It moved in its short, flowing dashes, all around him. It left a furrowed track behind it, it kicked up little spurts of sand as it made its dashes. It moved in closer.
    And he had it. He held it motionless, wrapped up as if he held it in many hands. He examined it, not closely, not analytically, but only enough so he could tell what kind of thing it was. Protoplasmic and heavily shielded against the radiations, even designed, perhaps – although he could not be sure – to take advantage of the energy contained in the radiation. An organism, more than likely, that could not exist without the radiations, that needed them as other creatures might need warmth, or food, or oxygen. Intelligent and laced with a multitude of emotions – not, perhaps, the kind of intelligence that could build a complex culture, but a high level of animal intelligence. Perhaps still evolving in its intelligence. Give it a few more million years and it might contrive a culture.
    He turned it loose. It flowed away, moving rapidly, straight away from him. He lost sight of it, but still could follow its movement for a time by its unreeling track and the spurts of sand it kicked into the air.
    There was much work to do. an atmospheric profile, an analysis of the soil and of the micro-organisms that it might contain, a determination of the liquid in the brook, an examination of the plant life, a geological survey, measurement of the magnetic field, the intensity of the radiation. But first there should be a general survey of the planet to determine what sort of place it was, a pin-pointing of those areas that might be of economic interest.
    And there it was again, another word he had not had before. Economic.
    He searched inside himself, inside the theoretical intelligence enclosed within the hypothetical force field, for the purpose that was hinted in that single word. When he found it, it stood out sharp and clear – the one thing he had found that was sharp and clear. What was here that could be used and what would be the cost of obtaining it? A treasure hunt, he thought. That was the purpose of him. It was clear immediately that he, himself, had no use for treasure of any kind at all. There must be someone else who would have a use for it. Although when he thought of treasure a pleasurable thrill went through him.
    What might there be in it for him, he wondered, this location of a treasure? What had been the profit to him in the finding of all those other treasures on all those other planets – although, come to think of it, there had not been treasure on every one of them. And on some of the others where there’d been, it had been meaningless, for planetary conditions had been such that it could not be got at. Many of the planets, he recalled, far too many of them, were such that only a thing such as himself would dare even to approach them.
    There had been attempts, he remembered now, to recall him from some of the planets when it had become apparent they had no economic worth and that to further explore them would be a waste of time. He had resisted those attempts; he had ignored the summons to return to wherever it was he went when he did return. Because, in his simplistic ethic, when there was a job to do he did it and he did not quit until the job was done. Having started something, he was incapable of leaving off until it had been finished. It was a part of him, this