Tan Porus parted the curtains with a sweep of his hand, and the five psychologists facing him averted their eyes. The streets of Earth's capital were deserted, of civilian population. The ordered tramp of the military patrolling the highways of the city sounded like a dirge. The wintry sky hung low over the scene of strewn bodies - and silence; the silence that follows an orgy of wild destruction.

'It was touch and go for a few hours there, colleagues.' Porus' voice was tired. 'If it had passed the city limits, we could never have stopped it.'

'Horrible, horrible!' muttered Hybron Prat. 'It was a scene a psychologist would have given his right arm to witness - and his life to forget.'

'And these are Humanoids!' groaned Kim Winson.

Semper Gor rose to his feet in sudden decision. 'Do you see the significance of this, Porus? These Earthmen are sheer uncontrolled atomite. They can't be handled. Were they twice the technological geniuses they are, they would be useless. With their mob psychology, their mass panics, their superemotional-ism, they simply won't fit into the Humanoid picture.'

Porus raised an eyebrow. 'Comet gas! Individually, we are as emotional as they are. They carry it into mass action and we don't; that's the only difference.'

'And that's enough!' exclaimed Tubal. 'We've made our decision, Porus. We made it last night, at the height of the… the… of it. The Solar System is to be left to itself. It is a plague spot and we want none of it. As far as the Galaxy is concerned, Homo Sol will be placed in strict quarantine. That is final!'

The Rigellian laughed softly. 'For the Galaxy, it may be final. But for Homo Sol?'

Tubal shrugged. 'They don't concern us.'

Porus laughed again. 'Say, Tubal. Just between the two of us, have you tried a time integration of Equation 128 followed by expansion with Karolean tensors?'

'No-o. I can't say I have.'

'Well, then, just glance up and down these calculations and enjoy yourself.'

The five scientists of the board grouped themselves about the sheets of paper Porus had handed them. Expressions changed from interest to bewilderment and then to something approaching panic.

Naru Helvin tore the sheets across with a spasmodic movement. 'It's a lie,' he screeched.

'We're a thousand years ahead of them now, and by that time we'll be advanced another two hundred years!' Tubal snapped. 'They won't be able to do anything against the mass of the Galaxy's people.'

Tan Porus laughed in a monotone, which is hard to do, but very unpleasant to hear. 'You still don't believe mathematics. That's in your behaviour pattern, of course. All right, let's see if experts convince you - as they should, unless contact with these off-normal Humanoids has twisted you. Joselin - Joselin Arn - come in here!'

The Centaurian commander came in, saluted automatically, and looked expectant.

'Can one of your ships defeat one of the Sol ships in battle, if necessary?'

Arn grinned sourly. 'Not a chance, sir. These Humanoids break Kraut's Law in panic - and also in fighting. We have a corps of experts manning our ships; these people have a single crew that functions as a unit, without individuality. They manifest a form of fighting - panic, I imagine, is the best word. Every individual on a ship becomes an organ of the ship. With us, as you know, that's impossible.

'Furthermore, this world's a mass of mad geniuses. They have, to my certain knowledge, taken no less than twenty-two interesting but useless gadgets they saw in the Thalsoon Museum when they visited us, turned 'em inside out and produced from them some of the most unpleasant military devices I've seen. You know of Julmun Thill's gravitational line tracer? Used - rather ineffectively - for spotting ore deposits before the modern electric potential method came in?

"They've turned it - somehow - into one of the deadliest automatic fire directors it's been my displeasure to see. It will automatically lay a gun or projector on a completely invisible target in space, air, water or rock, for that matter.'

'We,' said Tan Porus, gleefully, 'have far greater fleets than they. We could overwhelm them, could we not?' Joselin Arn shook his head. 'Defeat them now - probably. It wouldn't be overwhelming, though, and I wouldn't bet on it too heavily. Certainly wouldn't invite it. The trouble is, in a military way, this collection of gadget maniacs invent things at a horrible rate. Technologically, they're as unstable as a wave in water; our civilization is more like a sanddune. I've seen their ground-car plants install a complete plant of machine tools for production of a new model of automobile - and rip it out in six months because it's completely obsolete!

'Now we've come in contact with their civilization briefly. We've learned the methods of one new civilization to add to our previous two hundred and eighty-odd - a small percentage advantage. They've added one new civilization to their previous one - a one-hundred-percent advance!'

'How about,' Porus asked gently, 'our military position if we simply ignore them completely for two hundred years?'

Joselin Arn gave an explosive little laugh. 'If we could -which means if they'd let us - I'd answer offhand and with assurance. They're all I'd care to tackle right now. Two hundred years of exploring the new tracks suggested by their brief contact with us and they'd be doing things I can't imagine. Wait two hundred years and there won't be a battle; there'll be an annexation.'

Tan Porus bowed formally. Thank you, Joselin Am. That Was the result of my mathematical work.'

Joselin Arn saluted and left the room.

Turning to the five thoroughly paralyzed scientists, Porus went on: 'And I hope these learned gentlemen still react in a vaguely Humanoid way. Are you convinced that it is not up to us to decide to end all intercourse with this race? We may -but they won't!

'Fools' - he spat out the word - 'do you think I'm going to waste time arguing with you? I'm laying down the law, do you understand? Homo Sol shall enter the Federation. They are going to be trained into maturity in two hundred years. And I'm not asking you; I'm telling you!' The Rigellian stared up at them truculently.

'Come with me!' he growled brusquely.

They followed in tame submission and entered Tan Porus' sleeping quarters. The little psychologist drew aside a curtain and revealed a life-size painting.

'Make anything of that?'

It was the portrait of an Earthman, but of such an Earthman as none of the psychologists had yet seen. Dignified and sternly handsome, with one hand stroking a regal beard, and the other holding the single flowing garment that clothed him, he seemed personified majesty.

'That's Zeus,' said Poms. 'The primitive Earthmen created him as the personification of storm and lightning.' He whirled upon the bewildered five. 'Does it remind you of anybody?'

'Homo Canopus?' ventured Helvin uncertainly.

For a moment, Porus' face relaxed in momentary gratification and then it hardened again. 'Of course,' he snapped. 'Why do you hesitate about it? That's Canopus to the life, down to the full yellow beard.'

Then: 'Here's something else.' He drew another curtain.

The portrait was of a female, this time. Full-bosomed and wide-hipped she was. An ineffable smile graced her face and her hands seemed to caress the stalks of grain that sprang thickly about her feet.

'Demeter!' said Porus. 'The personification of agricultural fertility. The idealized mother. Whom does that remind you of?'

There was no hesitation this time. Five voices rang out as one: 'Homo Betelgeuse!'

Tan Porus smiled in delight. 'There you have it. Well?'

'Well?'said Tubal.

'Don't you see?' The smile faded. 'Isn't it clear? Nitwit! If a hundred Zeuses and a hundred Demeters were to land on Earth as part of a "trade mission," and turned out to be trained psychologists - Now do you see?'