The atomic bomb that was fired into the atmosphere of Sirius A-l, attained a velocity of thirty miles a minute. And so, in spite of the violently exploding energy flares that soared up to meet it, it penetrated to within forty miles of the planet's dimly visible surface before it was finally exploded by a direct hit.

In one hour, when the entire scene was still concealed by an impenetrable cloud, they had their first reaction. A transparent, glittering shell, not more than eight feet in diameter, was picked up on the scanners. There was something inside it, but whatever it was refused to resolve into focus.

It came nearer and nearer, and still the thing inside would not show clearly to the straining eyes.

Lesbee III stood on the bridge beside the chair in which his grandfather sat. And the sweat broke out on his brow. When the shell was two hundred yards distant, he said: 'Do you think we ought to let it come any nearer?'

The old man's glance was contemptuous. 'Our screens are up, aren't they? If it's a bomb, it can't touch us.'

Lesbee III was silent. He did not share the old man's confidence that Earth's science was equal to anything that might happen in space. He was prepared to admit that he knew very little about Earth's science, but still – that shell.

'It seems to have stopped, sir.' That was Carson, pointedly addressing the aged captain, ignoring the acting captain.

The words relieved Lesbee III, but the first officer's action saddened him. What kind of suicidal impulse made Carson think that the temporary presence of the hundred-year-old retired captain was a good reason for insulting the man who would be commander for thirty years more at least?

He forgot that, for the thing in the shell, whatever it was, was watching them intently. Lesbee III felt a hideous thrill. He said jumpily: 'Somebody get us a clear picture of it.'

The screen blurred, then cleared, but the object in the shell looked as confusing as ever. After a moment longer it moved in an unhuman fashion. Instantly the shell began to approach the spaceship again with a disturbingly steady forward movement. Within seconds, it was less than a hundred yards away, and coming nearer.

'He'll never get through the defenses!' Lesbee III said doubtfully.

He tensely watched the shell. At twenty-five yards it was already through the outer defenses not only of the ship but of Lesbee's mind. He couldn't see it. That was the damnable, mind-destroying part. His eyes kept twisting, as if his brain could not accept the image. The sensation was fantastic. His courage slipped from him like a rotted rag. He made a dive for the stairway and was vaguely surprised to find Carson there ahead of him. He felt the burly Browne crowding his heels.

Lesbee III's final memory of the bridge was of the ancient Captain Lesbee sitting stiffly in the great captain's chair – and the alien shell only a few feet from the outer hull.

In the corridor below, he recovered sufficiently to wave his officers to an elevator. He took them down to the alternative control room. They hastily switched on the viewplates that connected with the bridge. The screen flickered with streamers of light but no picture took form. And a steady roaring sound came from the speakers.

It was a dismaying situation; desperately, Lesbee III said, 'What could affect our eyes, twist them? Does anyone know of a phenomenon of the physics of light that has that effect?'

It seemed that a number of subvisual lasers could stimulate the visual centers painfully.

And certain levels of fear within the body could twist the eyes from inside.

Those were the only suggestions.

Lesbee III commanded: 'Rig something that will reflect the particular lasers you have in mind.' To Dr. Kaspar, he said, 'What would stimulate fear?'

'Certain sounds.'

'There were none.'

'Brain– level waves on the exact band of terror.'

'Wel– ll' -doubtfully – 'we were certainly put to flight, but I didn't actually feel fear. I felt confusion.'

'Some kind of an energy field – I'm speculating wildly!' said the psychologist.

'Use the technical staff!' Lesbee III ordered him. 'Figure out some kind of interference for all of those possibilities. On the double, everybody!'

They were still frantically working in the shops, when the viewplate in the alternative control room suddenly cleared. Simultaneously, the roar in the speakers ceased. The first picture that showed was of the bridge itself. Lesbee III could see the old captain still in his chair, but slumped over. There was nothing else visible in his line of sight. Hopefully, Lesbee III tuned to the space scanners. To his relief, he saw that the shell was withdrawing; it was already a quarter of a mile away. It receded rapidly, became a speck against the great, misty planet below.

Lesbee III did not wait for it to vanish entirely, but raced for the elevator – with Browne and Carson close behind. They found his grandfather still alive, talking nonsense to himself and, it soon developed, stone blind.

As they carried him down the steps, and then wheeled him to his room, Lesbee listened intently to his muttering. The words that made sense were about the old man's childhood long ago on Earth.

In the room, Lesbee III grasped the thin, cold hands in his own. 'Captain! Captain!'

After he had repeated the one word several times, the other's muttering ceased. 'Captain, what happened up there on the bridge?'

The old man started to speak. Lesbee III strained and heard a few words:

'... we forgot the eccentric orbit of Canis Major A with its B. We forgot that B is one of the strange suns of the galaxy... so dense, so monstrously dense... it said it's from the planet of B... It said, get away! They won't deal with anyone who tried to bomb them... Get away! Get away...! It attached something to the hull... pictures, it said...'

Lesbee III had leaped away to the intercom. He shouted orders for astronauts to go outside, remove whatever was attached to the hull, take it off in a lifeboat, and when they had examined it and found it harmless, bring it back to the ship.

As he turned back to the captain, Lesbee III felt a shock. The face which had momentarily showed some semblance of sanity had changed again. The eyes were all wrong, twisted, crossed, as if they had tried to look at something that they could not focus on. As he watched, more interested now than disturbed, they continued to twist sightlessly.

Lesbee III tried to get the old man's attention as before by addressing him repeatedly. But this time there was no response. The lined and bearded face retained its abnormal expression.

A doctor had come. Two assistants undressed the long, scrawny body and laid it in the bed. Lesbee III departed.

By the dinner hour, the astronauts were back with a weird but harmless package. It contained a transparent, peculiarly-shaped beaker with a colorless liquid inside. When Lesbee III first saw the object, he saw that there was a picture on the inside of the bottle. Eagerly, he picked it up – intending to bring it closer to his eyes – and the picture changed. Another scene took form inside.

The picture changed with every move. Not once, while he looked at it, did any scene repeat. And in order to see a specific frame for more than a fraction of a second, he finally had to lay it down and sit up close to it. By maneuvering it gently with his fingers every few seconds, he was able at last to view the strange world of the inhabitants of Sirius A-l, who, apparently, had originally come from the mysterious planet of B.

At first there were only scenes: landscapes and oceans. What the liquid in the oceans was, was not obvious; the water was tinted yellow. But the initial scenes showed a turbulent liquid that had the look of being storm tossed.