McCauley floated over to the packed-up air system. In a space voyage up to a week in length, it is as economical of weight to carry air as to purify it. But the Venus shoot would last much, much longer than a week. So McCauley unpacked the air system. The vegetation had been padded lest it be bruised or broken in the take-offs. He set up the unit and started the hydroponic pump. Randy adjusted the drinkables unit. McCauley set out meals to thaw, in readiness for dinner. Randy put the sanitary facilities and the waste-disposal unit in operation. In effect, the ship had had to be decommissioned as a livable vessel while it was being flung out from Earth as a projectile. Now, in far space and going even farther, the two men transformed it into one of those specialized environments that supply men in emptiness with everything they require except day, night, weight, up, down, normal sounds, and a feeling of belonging where they are. One homey touch appeared before the recommissioning of the ship was complete. McCauley opened a very small box and took from it an infinitesimal yellow object that stirred as he handled it. It was a tiny canary which had been stowed in the equivalent of a canary-sized acceleration chair. Now it struggled desperately in his hand. "You'll do, Mr. Perkins," said McCauley. "You're all right!" He put the panting little creature--Mr. Perkins--into a cage hardly larger than itself. It let out a bewildered chirp when he released it. It struggled wildly, in panic because there was no up or down. McCauley captured it and put its groping claws against the perch. They gripped it. He set up a curiously intricate device inside the cage. "He'll do," he said in satisfaction. "And it looks as if his food-and-water system is going to work, even in no-gravity. That was a job to design!" He checked two larger devices with extreme care. One was the flare-particle counter, designed to make an audible click for every hundred, every thousand, or every ten-thousand flare-particle penetrations registered. McCauley set it for hundreds. It clicked every three or four seconds, which was a high concentration but still within the tolerance limit. The other device was the oxygen-supply flutter valve. The plants in the air system would absorb carbon dioxide from the air as the men's breaths produced it, and release oxygen to replace it. But it was not quite a hundred per cent replacement. From time to time more oxygen had to be added from storage tanks to keep the air volume constant and the oxygen percentage right. The flutter valve took care of all this. It made a curiously irritable, buzzing sound when it worked.