Quinby rose eagerly, his blond head towering above the little old executive. "You mean my usuform--" "Your usuform, sir, is indubitably the greatest cook since the Golden Age before the devilish introduction of concentrates. Do you mind if I share your box for this great exhibition?" Quinby beamed and introduced him to Mike. Grew shook hands warmly with our foreman, then turned to me and spoke even my name with friendly pleasure. Before anybody could say any more, before I could even wipe the numb dazzle off my face, the Head's voice began to come over the speaker. His words were few--just a succinct promise of the wonders of usuforms and their importance to our civilization--and by the time he'd finished the dowser was in place on the field. To everybody watching but us, there was never anything that looked less like a robot. There wasn't a trace of an android trait to it. It looked like nothing but a heavy duralite box mounted on caterpillar treads. But it was a robot by legal definition. It had a Zwergenhaus brain and was capable of independent action under human commands or direction. That box housed the brain, with its _n_th-sensory perception, and eyes and ears, and the spike-laying apparatus. For when the dowser's perception of water reached a certain level of intensity, it layed a metal spike into the ground. An exploring party could send it out on its own to survey the territory, then follow its tracks at leisure and dig where the spikes were. After the Head's speech there was silence. Then Quinby leaned over to the mike in our box and said "Go find water." The dowser began to move over the field. Only the Head himself knew where water had been cached at various levels and in various quantities. The dowser raced along for a bit, apparently finding nothing. Then it began to hesitate and veer. Once it paused for noticeable seconds. Even Quinby looked tense. I heard sharp breaths from Sanford Grew, and Mike almost drained his shaker. Then the dowser moved on. There was water, but not enough to bother drilling for. It zoomed about a little more, then stopped suddenly and definitely. It had found a real treasure trove. I knew its mechanism. In my mind I could see the Zwergenhaus brain registering and communicating its needs to the metal muscles of the sphincter mechanism that would lay the spike. The dowser sat there apparently motionless, but when you knew it you had the impression of a hen straining to lay. Then came the explosion. When my eyes could see again through the settling fragments, there was nothing in the field but a huge crater. It was Quinby, of course, who saw right off what had happened. "Somebody," my numb ears barely heard him say, "substituted for the spike an explosive shell with a contact-fuse tip." Sanford Grew nodded. "Plausible, young man. Plausible. But I rather think that the general impression will be simply that usuforms don't work." He withdrew, smiling gently.