The seat covers were made of plastic in a maroon and blue plaid pattern. But where the box had rested there was a dirty grey rectangular patch that hadn't been there before.

Forster stared, then opened the door again. He rubbed his fingers over the discolored spot; it felt no different than the rest of the fabric. Then he placed the box over the area--it fitted perfectly.

He flopped down on the seat, his legs dangling out of the car, fighting down a sudden irrational wave of panic. He pushed the container to the other end of the seat.

_After all_, he rationalized, _plastics are notoriously unstable under certain conditions. This is probably a new alloy Washington wants tested for behavior under extreme conditions of temperature and pressure. What's gotten into you?_

He took a deep breath, picked up the box again. Where it had rested there was another discolored patch on the car seat covers.

Holding it away from him, Forster hurried into the office, then dumped the box into a metal wastebasket. Then he went to a cabinet and pulled out a Geiger counter, carried it over to the wastebasket. As he pointed the probe at the box the familiar slow clicking reassured him, and feeling a little foolish he put the instrument back on its shelf.

[Illustration: In his pressurized chamber, Forster read the startling message.]

Hurriedly, he went through his mail; there was nothing in it referring to the package. Then he called the classified filing section; nobody there knew anything about it either.

For some reason he couldn't explain to himself, he wasn't even surprised.

He stared into the wastebasket. The clumsily etched instructions glinted up at him: "_To be opened as soon as possible...._"

He picked up the phone and called the decompression chamber building.

* * * * *

There was no valid reason why he should have been self-conscious as he talked to the lab attendant in charge of the decompression tank. He used it a dozen times a month for tests and experiments, yet when he gave his instructions his voice was labored and strained.

"Some genius in Washington sent this thing down without any covering instructions, but it has to be opened in a hurry in a thin atmosphere. Er--I'd like you to stay on the intercom for a while in case it blows up in my face or something." He tried to laugh, but all that came out was a croak.

The attendant nodded indifferently, then helped Forster into the helmet of his pressure suit. He climbed up the steps into the chamber, pulling the airtight door shut behind him. He placed the box on the desk in front of the instrument panel, then turned back to push the door clamps into place.

For the first time in the hundreds of hours he'd spent in the tank, he knew the meaning of claustrophobia.

Mechanically, he plugged in his intercom and air lines, went through the other routine checks before ascent, tested communications with the lab attendant, then flicked the exhaust motor switch.

Now there was little to do except wait.