The beeping sounds continued to come in from space. The second message remained the same but the crackling sounds changed. There was a systematic and consistent variation in what they apparently had to say. M.I.T. discovered the modification. When its report reached the newspapers, Sandy invaded the construction shed to show Burke the news account. Oil-smeared and harassed, he stopped work to read it. "Hell!" he said querulously. "I should've had somebody watching for this! I figured the second broadcast was telling us something that would change as time went on. They're telemetering something to us. I'd guess there's an emergency or an ultimatum in the works, and this is telling how fast it's coming to a crisis. But I'm already working as fast as I can!" "Some cases marked 'Instruments' came this morning," Sandy told him. "They're the solidest shipping cases I ever saw. And the bills for them!" "Wire Keller," said Burke. "Tell him they're here and to come along." "Who's Keller?" asked Sandy. "And what's his address?" Burke blew up unreasonably, and Sandy said "I quit!" In seconds, he had apologized and assured Sandy that she was quite right and that he was an idiot. Of course she couldn't know who Keller was. Keller was the man who would install the instruments in the ship outside. Burke gave her his address. Sandy was not appeased. Burke ran a grimy hand despairingly through his hair. "Sandy," he protested, "bear with me just a little while! In just a few more days this thing will be finished, and I'll know whether I'm the prize imbecile of history or whether I've actually managed to do something worth while! Bear with me like you would with a half-wit or a delinquent child or something. Please, Sandy--" She turned her back on him and walked out of the shed. But she didn't quit. Burke turned back to his work. The Russians sent up another probe. It went off course. There were now six unmanned Russian probes in emptiness, of which four were lined up reasonably well along the route which a manned probe, if one were sent up, should ultimately travel. The advance probes formed an ingenious approach to the problem of getting a man farther out in space than any man had been before, but it was horribly risky. But apparently the Russians could afford to take such risks. The Americans couldn't. They had a settled policy of spending a dollar instead of a man. It was humanitarian, but it had one drawback. There was a tendency to keep on spending dollars and not ever let a man take a chance. The Russians had four fuel-carrying drones in line out in space. If a ship could grapple them in turn and refuel, it might make the journey to M-387 in eight or ten weeks instead of as many months. But it was not easy to imagine such a success. And as for getting back.... The beeping sounds continued to be received by Earth.