The youth was nodding. He felt reluctant to discuss this particular subject, and so it was time to end the conversation. There was another question in his mind, having to do with the relationship of the older Lesbee with Tellier's widow since his mother's death. But a moment's consideration convinced him that such an inquiry was not in order.

'Thanks, Dad,' he said, and walked on to his room.

For weeks they had been slowing down. And, day by day, the bright stars in the blackness ahead grew larger and more dazzling. The four suns of Alpha Centauri no longer looked like one brilliant diamond, but were distinct units separated by noticeable gaps of black space.

They passed Proxima Centauri at a distance of over two billion miles. The faint red star slowly retreated behind them.

Not Proxima the red, the small, but Alpha A was their first destination. From far Earth itself, the shadow telescopes had picked out seven planets revolving around A. Surely, of seven planets, one would be habitable.

When the ship was still four billion miles from the main system, Lesbee II's six-year-old son came to him in the hydroponic gardens – where he had been called to settle a discussion on the uses of solid state coolants in growing vegetables and fruit.

'Grandfather wants to see you, Dad, in the captain's cabin.'

Lesbee nodded, and noted that the boy ignored the workers in the gardens. He felt vaguely pleased. It was well for people to realize their station in life. And, ever since the boy's birth, several years after the crisis created by Ganarette, he had consciously striven to instill the proper awareness into the youngster.

The boy would grow up with that attitude of superiority so necessary to a commander.

Lesbee forgot that. He tugged the youngster along to the playground adjoining the residential section, then took an elevator to the officers' deck. His father, four physicists from the engineering department, and Mr. Carson, Mr. Henwick, and Mr. Browne were in conference as he entered. Lesbee sank quietly into a chair at the outer edge of the group, but he knew better than to ask questions.

It didn't take long to realize what was going on. The sparks. For days the ship had been moving along through what seemed to be a violent electric storm. The sparks spattered the outer hull from stem to stern. On the transparent bridge it had become necessary to wear dark glasses; the incessant firefly-like flares of light upset the muscular balance of the eyes, and caused strain and headache.

The manifestation was getting worse, not better.

'In my opinion,' said the chief physicist, Mr. Plauck, 'we have run into a gas cloud – as you know, space is not a total vacuum, but is occupied, particularly in and near star systems, by large numbers of free atoms and electrons. In such a complicated structure as is created by the Alpha A, B, C, and Proxima suns, gravity pull would draw enormous masses of gas atoms from the outer atmospheres of all the stars, and these would permeate all the surrounding space. As for the electrical aspects, apparently a disturbance, a flow, has been set up in these gas clouds, possibly even caused by our own passage, though that is unlikely. Interstellar electrical storms are not new.'

He paused and glanced at one of his assistants questioningly. The man, a mousy individual named Kesser, said:

'It happens that I'm in disagreement with the electrical-storm theory, though I also agree on the presence of masses of gas. After all, that's old stuff in astronomy. But now – my explanation for the sparks. As long ago as the twentieth century, perhaps even earlier, it was theorized that the gas molecules and atoms floating in space readily interchanged velocity for heat or heat for velocity. The temperatures of these free particles, when such an interchange occurred, was found to be as high as twenty thousand degrees Fahrenheit.'

He looked around, momentarily very unmouselike. 'What would happen if a molecule traveling at such speed struck our ship? Sparks of heat, of course.' He paused. He was a graying man with a hesitant way of speaking. 'And then, of course, we must always remember the first Centaurus expedition and be doubly careful.'

There was a chilled silence. It was strange but Lesbee II had the impression that, although everybody had been thinking of the first expedition, nobody wanted it mentioned.

Lesbee II glanced at his father. Captain Lesbee was frowning. The commander had grown more spare with years, but his six feet three inches still supported 175 pounds of bone and flesh. He said:

'It is taken for granted that we shall be cautious. One of the purposes of this voyage is to discover the fate of the first expedition.' His gaze flashed toward the group of physicists. 'As you know,' he said, 'that expedition set out for Alpha Centauri nearly seventy-five years ago. We are assuming that the engines would have kept going. Therefore, some control would have existed in any fall through the atmosphere of a planet, and a trace of its presence will remain. The question is, what would be operable after three quarters of a century?'

Lesbee was amazed at the various answers. There were so many things that the physicists expected would survive. The 'pile' engines. All electronic detectors and many other energy sources. It was also noted that printed instruments could withstand 800 gravities. The shell of the ship? Its survival would depend on the velocity of the ship as it fell through the planet's atmosphere. It was theoretically possible that the speed would be vast beyond all safety limits. At such immense speeds, the entire machine would go up in a puff of heat energy.

But that was not what the experts anticipated. There should be something. 'We should be able to trace the ship within hours of arriving at the planet where it crashed.'

As the men got up to leave, Lesbee caught his father's signal for him to remain behind. When the others had gone, the older man said, 'It is necessary to make plans against a second rebellion. There is a scheme afoot to evade our connection with Earth law by establishing a permanent colony on Centaurus and never returning to Earth. Since, as you know, in my view there is no Earth to go back to, this new development baffles me. It still seems to be in our favor that people do believe that Earth survives. But I must advise you that this time the rebels do not intend to make you captain. Let us, therefore, discuss tactics and strategy-'

Watch duty became a nightmare. The three chief officers and Lesbee divided it into three-hour shifts that ran consecutively. They wore semispace suits for protection when they were on the bridge, but Lesbee's eyes never stopped aching.

During his sleep period, he dreamed of sparks dancing with an unsteady beat under his eyelids, and there was a picture of a successful mutiny led by Ganarette, surprising them in spite of their preknowledge. It was miraculous that his father knew as much as he did about the plot.

The speed of the ship came down to interplanetary levels. And, slowly, they drew near the planet they had selected for a first landing. It was the only possible selection. Of the seven planets in the system, six had already been measured as being of Jupiter size; this seventh one had a diameter of ten thousand miles. At 120 million miles from Alpha A, a sun 15 per cent hotter than Sol, it almost approximated Earth conditions. There was the added complication of the pale but sun-sized star, Alpha B, visible in the blackness little more than a billion miles from Alpha A, and the almost invisible C, too, would have its effect. But that scarcely mattered beside the fact that here was a planet of approximately the right size, and even at a distance it glowed with a jewel-like atmosphere.