give him. for, of course, being Malcolm's duplicate, he too carried in his loins the fatal Makenzie gene.
Sooner than he had expected, he had to prepare his family for the new addition. After the usual
number of experiments, he had settled down with Marissa four years ago, and he loved her children as
much, he was certain, as if they had been his own flesh and blood. Clyde was now six years old, Carline three. They in their turn appeared to be as fond of Duncan as of their real fathers, who were now regarded as honorary members of Clan Makenzie. Much the same thing had happened in Colin's generation — he
had acquired or adopted three families — and in Malcolm's. Grandfather had never gone to the trouble of marrying again after Ellen had left him, but he had never lacked company for long. Only a computer
could keep track of the comings and goings on the periphery of the clam; it often seemed that most of
Titan was related to it in some way or other. One of Duncan's major problems now was deciding who
would be mortally offended if he failed to say good-bye.
Quite apart from the time factor, he had other reasons for making as few farewells as possible. Every
one of his friends and relatives — as well as almost complete strangers — seemed to have some request
for him, some mission they wanted him to carry out as soon as he reached Earth. Or, worse still, there was some essential item ("It won't be any trouble") they wanted him to bring back. Duncan calculated that he would have to charter a special freighter if he acquiesced to all these demands.
Every job now had to be divided into one of two categories. There were the things that must be done
before he left Titan, and those that could be postponed until he was aboard ship. The latter included his studies of current terrestrial affairs, which kept slipping despite Colin's increasingly frantic attempts to update him.
Extricating himself from his official duties was also no easy task, and Duncan realized that in a few
more years it would be well-nigh impossible. He was getting involved in too many things, though that
was a matter of deliberate family policy. More than once he had complained that his title of Special
Assistant to the Chief Administrator gave him responsibility without power. To this, Chief Administrator Colin had retorted: "Do you know what power means in our society? Giving orders to people who carry them out — only if and when they feel like it."
This was, of course, a gross libel on the Titanian bureaucracy, which functioned surprisingly well and with a minimum of red tape. Because all the key individuals knew each other, an immense amount of
business got done through direct personal contact. Everyone who had come to Titan had been carefully
selected for intelligence and ability, and knew that survival depended upon co-operation. Those who felt like abandoning their social responsibilities first had to practice breathing methane at a hundred below.
One possible embarrassment he had at least been spared. He could hardly leave Titan without saying
good-bye to his once closest friend — but, very fortunately, Karl was off-world. Several months ago he had left on one of the shuttles to join a Terran survey ship working its way through the outer moons.
Ironically enough, Duncan had envied Karl his chance of seeing some unknown worlds; now it was Karl
who would be envious when he heard that Duncan was on his way to Earth. The thought gave him more
sadness than pleasure; the Makenzies, whatever their faults, were not vindictive. Yet Duncan could not help wondering how often Karl's reveries would now turn sunward, and to the moment long ago when
their emotions had been irrevocably linked with the mother world.
Duncan was just sixteen, and Karl twenty-one, when the cruise liner Mentor had made her first, and it
was widely hoped only, rendezvous with Titan. She was a converted fusion-drive freighter — slow but
economical, provided adequate supplies of hydrogen could be picked up at strategic points.
Mentor had stopped at Titan for her final refueling, on the last leg of a grand tour that had taken her to Mars, Ganymede, Europa, Pallas, and Iapetus, and had included fly-bys of Mercury and Eros. As soon
as she had loaded some fifteen thousand tons of hydrogen, her exhausted crew planned to head back to
Earth on the fastest orbit they could compute, if possible after marooning all the passengers.
The cruise must have seemed a good idea when a consortium of Terran universities had planned it
several years earlier. And so indeed it had turned out, in the long run, for Mentor graduates had since proved their worth throughout the Solar System. But when the ship staggered into her parking orbit,
under the command of a prematurely gray captain, the whole enterprise looked like a first-magnitude
disaster.
The problems of keeping five hundred young adults entertained and out of mischief on a six-months'