Laro nodded, perfectly matter-of-factly, and in Hilton's mind there formed a picture. It was not clear, but it showed plainly enough a long line of aliens approaching the _Perseus_. Each carried on his or her shoulder a lead container holding two hundred pounds of Navy Regulation fuel pellets. A standard loading-tube was sealed into place and every fuel-hold was filled. This picture, Laro indicated plainly, could become reality any time. Sawtelle was notified and came on the run. "No fuel is coming aboard without being tested!" he roared. "Of course not. But it'll pass, for all the tea in China. You haven't had a ten per cent load of fuel since you were launched. You can fill up or not--the fuel's here--just as you say." "If they can make Navy standard, of course we want it." The fuel arrived. Every load tested well above standard. Every fuel hold was filled to capacity, with no leakage and no emanation. The natives who had handled the stuff did not go away, but gathered in the engine-room; and more and more humans trickled in to see what was going on. Sawtelle stiffened. "What's going on over there, Hilton?" "I don't know; but let's let 'em go for a minute. I want to learn about these people and they've got me stopped cold." "You aren't the only one. But if they wreck that Mayfield it'll cost you over twenty thousand dollars." "Okay." The captain and director watched, wide eyed. Two master mechanics had been getting ready to re-fit a tube--a job requiring both strength and skill. The tube was very heavy and made of superefract. The machine--the Mayfield--upon which the work was to be done, was extremely complex. Two of the aliens had brushed the mechanics--very gently--aside and were doing their work for them. Ignoring the hoist, one native had picked the tube up and was holding it exactly in place on the Mayfield. The other, hands moving faster than the eye could follow, was locking it--micrometrically precise and immovably secure--into place. "How about this?" one of the mechanics asked of his immediate superior. "If we throw 'em out, how do we do it?" By a jerk of the head, the non-com passed the buck to a commissioned officer, who relayed it up the line to Sawtelle, who said, "Hilton, _no_body can run a Mayfield without months of training. They'll wreck it and it'll cost you ... but I'm getting curious myself. Enough so to take half the damage. Let 'em go ahead." "How _about_ this, Mike?" one of the machinists asked of his fellow. "I'm going to _like_ this, what?" "Ya-as, my deah Chumley," the other drawled, affectedly. "My man relieves me of _so_ much uncouth effort."