consciousness is two and a half minutes."

Baker sipped his coffee, watching the faces of the two men. The clock on his desk moved past two minutes. Two and a half minutes. Baker shrugged. He knew there were some exceptions. Some persons in superior physiological condition had proved in aeronautical tests on Earth to be able to go on for as long as four minutes in as rarefied oxygen as existed here. But no more than four minutes.

The clock hand reached four minutes. The men still sat there.

He had timed them wrong. He had missed a minute. Certainly. They were going to start sagging now. Now.

Another minute went by. Another minute. The men sat there, looking straight at him through the tele-screen. There was a cynical smile on their faces, as if they knew the camera was on them—as if they could actually see him.