‘Then the Dome is more of a device to keep normal light in, so to speak, rather than to keep anything out.’

‘We don't even keep air out. The air and water that circulates in the Dome is drawn from Erythro's planetary supply. Naturally, though, we're careful to keep something out,’ said Genarr. ‘We keep out the prokaryotes. You know, the little blue-green cells.’

Insigna nodded thoughtfully. That had turned out to be the explanation for the oxygen content in the air. There was life on Erythro, even all-pervasive life, but it was microscopic in nature, only equivalent to the simplest forms of cellular life in the Solar System.

She said, ‘Are they really prokaryotes? I know that's what they're called, but that's what our bacteria are also called. Are they bacteria?’

‘If they're equivalent to anything in the history of Solar System life, it is to the cyanobacteria, those that photo-synthesize. You're right to ask the question, though. No, they're not our cyanobacteria. They possess nucleoprotein, but with a structure fundamentally different from that which prevails in our form of life. They also have a kind of chlorophyll that lacks magnesium and works on infrared so that the cells tend to be colorless rather than green. Different enzymes, trace minerals in different proportions. Still, they resemble Earth cells sufficiently in outer appearance to be called prokaryotes. I understand that biologists are pushing for the word “erythryotes” but for nonbiologists like ourselves, prokaryotes is good enough.’

‘And they're efficient enough in their workings to account for the oxygen in Erythro's atmosphere?’

‘Absolutely. Nothing else could possibly explain its existence there. By the way, Eugenia, you're the astronomer, so what's the latest thinking on how old Nemesis might be?’

Insigna shrugged. ‘Red dwarfs are next to being immortal. Nemesis can be as old as the Universe and still go on for another hundred billion years or so without visible change. The best we can do is judge by the contents of the minor elements making up its structure. Supposing that it's a first-generation star and didn't begin with anything beyond hydrogen and helium, it is a bit over ten billion years old - a little more than twice the age of the Sun of the Solar System.’

‘Then Erythro is ten billion years old, too.’

‘Absolutely. A stellar system is formed all at once and not piecemeal. Why are you asking?’

‘It just strikes me as odd that in ten billion years, life hasn't got past the prokaryote stage.’

‘I don't think that's surprising, Siever. On Earth, for somewhere between two and three billion years after life first appeared, it remained strictly prokaryote, and here on Erythro the energy concentration in sunlight is far less than it is on Earth. It takes energy to form more complicated life-forms. This sort of thing has been pretty well discussed among the Rotorians.’

‘I'm sure of it,’ said Genarr, ‘but it doesn't seem to reach us here at the Dome. Our minds are too fixed, I suppose, on our local duties and problems - though you'd think anything to do with the prokaryotes would come under that heading.’

‘For that matter,’ said Insigna, ‘we don't hear much about the Dome on Rotor.’

‘Yes, things tend to compartmentalize. But then, of course, there's nothing glamorous about the Dome, Eugenia. It's just a workshop, so I'm not surprised it gets lost in the press of events on Rotor. It's the new Settlements that are being built that get all the attention. Are you going to move to one of them?’

‘Never. I'm a Rotorian, and I intend to stay one. I wouldn't even be here - if you'll pardon my saying so - if it weren't an astronomical necessity. I've got to make a number of observations from a base that is more stable than Rotor.’

‘So I have been informed by Pitt. I am instructed to give you my full cooperation.’

‘Good. I'm sure you will. Incidentally, you mentioned earlier that the Dome would like to keep the prokaryotes out. Do you succeed in doing so? Is the water here safe to drink?’

Genarr said, ‘Obviously, since we drink it. There are no prokaryotes in the Dome. Any water that comes in - anything at all that comes in - is bathed in blue-violet light that destroys the prokaryotes in a matter of seconds. The short-wave photons in the light are too energetic for the little things and break down key components of the cells. And even if some of them come in, they're not poisonous, as far as we can tell, or harmful in any way. We've tested them on animals.’

‘That's a relief.’

‘It works the other way, too. Our own microorganisms can't compete with Erythro's prokaryotes under Erythrotic conditions. At least when we seed Erythro's soil with our own bacteria, they don't succeed in growing and multiplying.’

‘What about multicellular plants?’

‘We've tried it, but with very poor results. And it must be due to the quality of Nemesis' light because we can grow plants perfectly well inside the Dome, using Erythro's soil and water. We report these things back to Rotor, of course, but I doubt that the information gets widely publicized. As I said, Rotor isn't interested in the Dome. Certainly the fearsome Pitt isn't interested in us, and he's really all that counts on Rotor, isn't he?’

Genarr said that with a smile, but the smile seemed strained. (What would Marlene have said about it, Insigna wondered.)

She said, ‘Pitt isn't fearsome. He's sometimes tiresome , but that's a different thing. You know, Siever, I always thought when we were young that you might be Commissioner someday. You were enormously bright, you know.’

‘Were?’

‘Still are, I'm sure, but in those days you were so politically oriented, had such ideas. I used to listen to you, entranced. In some ways, you would have been a better Commissioner than Janus is. You would have listened to people. You wouldn't have insisted on getting your own way as much.’

‘Which is precisely why I would have made a very poor Commissioner. You see, I don't have any precise goals in life. I just have the desire to do what seems to me to be the right thing at the moment, in the hope that it will end up with something bearable. Now, Pitt knows what he wants and intends to get there by any means.’

‘You're misjudging him, Siever. He's got strong views, but he's a very reasonable man.’

‘Of course, Eugenia. That's his great gift, his reasonableness. Whatever course he pursues, he always has a perfectly good, a perfectly logical, a perfectly human reason for it. He can make one up at any given moment, and is so sincere about it, he convinces even himself. I'm sure if you've had any dealings with him, you've managed to let him talk you into doing what you at first didn't want to do, and that he won you over not by orders and threats but by very patient, very rational arguments.’

Insigna said weakly, ‘Well-’

At that, Genarr added sardonically, ‘I see you have indeed suffered from his reasonableness. You can see for yourself, then, what a good Commissioner he is. Not a good person, but a good Commissioner.’

‘I wouldn't go so far as to say he wasn't a good person, Siever,’ said Insigna, shaking her head slightly.

‘Well, let's not argue about it. I want to meet your daughter.’ He rose to his feet. ‘Why don't I visit your quarters after dinner?’

‘That would be delightful,’ said Insigna.

Genarr looked after her with a fading smile as she left. Eugenia had wanted to reminisce, and his own first reaction was to mention her husband - and she had frozen.

He sighed inwardly. He still had that extraordinary faculty of ruining his own chances.

Eugenia Insigna said to her daughter, ‘His name is Siever Genarr, and he is properly addressed as Commander, because he's the head of the Erythro Dome.’

‘Of course, Mother. If that's his title, I'll call him that.’

‘And I don't want you to embarrass him-’

‘I wouldn't do that.’

‘You would do so all too easily, Marlene. You know that. Just accept his statements without correcting them on the ground of body language. Please! He was a good friend of mine at college and for a while afterward. And even though he's been here in the Dome for ten years and I haven't seen him in all that time, he's still an old friend.’

‘I think he must have been a boyfriend.’

‘Now that's just what I mean,’ said Insigna. ‘I don't want you watching him and telling him what he really means or thinks or feels. And for your information, he was not my boyfriend, exactly, and we were certainly not lovers. We were friends and we liked each other - as friends. But after your father-’ She shook her head, and gestured vaguely. ‘And be careful what you say about Commissioner Pitt - if that subject comes up. I get the feeling Commander Genarr distrusts Commissioner Pitt-’

Marlene bestowed one of her rare smiles on her mother. ‘Have you been studying Commander Siever's subliminal behavior? Because what you have is more than a feeling.’

Insigna shook her head. ‘You see? You can't stop for a moment. Very well, it's not a feeling. He actually said he didn't trust the Commissioner. And you know,’ she added, half to herself, ‘he may have reason-’

She turned to Marlene and said suddenly, ‘Let me repeat, Marlene. You are perfectly free to watch the Commander and find out all you can, but don't say anything to him about it. Tell me ! Do you understand?’

‘Do you think there's danger, Mother?’

‘I don't know.’

‘I do,’ said Marlene matter-of-factly. ‘I've known there was danger as soon as Commissioner Pitt said we could go to Erythro. I just don't know what the danger is.’

Seeing Marlene for the first time was a shock to Siever Genarr, one that was made worse by the fact that the girl looked at him with a sullen expression that made it seem that she knew perfectly well that he had received a shock, and just why.

The fact was that there was not a thing about her that seemed to indicate she was Eugenia's daughter, none of the beauty, none of the grace, none of the charm. Only those large bright eyes that were now boring into him, and they weren't Eugenia's either. They were the one respect in which she exceeded her mother, rather than fell short.

Little by little, though, he revised his first impression. He joined them for tea and dessert, and Marlene behaved herself with perfect propriety. Quite the lady, and obviously intelligent. What was it that Eugenia had said? All the unlovable virtues? Not quite that bad. It seemed to him that she ached for love, as plain people sometimes do. As he himself did. A sudden flood of fellow feeling swept over him.