'I think you mean "potential," Dr. Ullen!' Thorning sighed audibly.

'Well, if you say so. Anyway, dis "potential" changes also very fast and de two changes are synchronized somehow along wid magnetism dat - uh - shifts and dat's all I know about it.' He smiled uncertainly, 'I would like to go back now. It would be all right now, wouldn't it?'

The Admiral vouchsafed no answer, 'Do you make anything out of that mess, Doctor?'

'Damned little,' admitted the physicist, 'but it gives me a lead or two. We might try getting hold of this Beg's book, but there's not much hope. It will simply repeat what we've just heard. Dr. Ullen, are there any scientific works on your planet?'

The Martian saddened, 'No, Dr. Doming, dey were all destroyed during de Kalynian reaction. On Mars, we doroughly disbelieve in science. History has shown dat it comes from science no happiness.' He turned to the young Earthman at his side, 'Johnnie, let us go now, please.'

Korsakoff dismissed the two with a wave of the hand.

Ullen bent carefully over the closely-typed manuscript and inserted a word. He glanced up brightly at Johnnie Brewster, who shook his head and placed a hand on the Martian's arm. His brow furrowed more deeply.

'Ullen,' he said harshly, 'You're in trouble.'

'Eh? I? In trouble? Why, Johnnie, dat is not so. My book is coming along famously. De whole first volume, it is completed and, but for a bit of polishing, is ready for de printers.'

'Ullen, if you can't give the government definite information on the disintegrator, I won't answer for the consequences.'

'But I told all I knew-'

'It won't do. It's not enough. You've got to remember more, Ullen, you've got to.'

'But knowledge where dere is none is impossible to have -dat is an axiom.' Ullen sat upright in his seat, propping himself on a crutch.

'I know it,' Johnnie's mouth twisted in misery, 'but you've got to understand.

'The Venusians have control of space; our Asteroid garrisons have been wiped out, and last week Phobos and Deimos. fell. Communications between Earth and Luna are broken and God knows how Jong the Lunar squadron can hold out. Earth itself is scarcely secure and their bombings are becoming more serious- Oh, Ullen, don't you understand?'

The Martian's look of confusion deepened, 'Eard is losing?'

'God, yes!'

'Den give up. Dat is de logical ding to do. Why did you start at all - you stupid Eardmen.'

Johnnie ground his teeth, 'But if we have the disintegrator, we won't lose.'

Ullen shrugged, 'Oh, Johnnie, it gets wearisome to listen to de same old story. You Eardmen have one-track minds. Look, wouldn't it make you feel better to have me read you some of my manuscript? It would do your intellect good.'

'All right, Ullen, you've asked for it, and here's everything right out. If you don't tell Thorning what he wants to know, you're going to be arrested and tried for treason.'

There was a short silence, and then a confused stutter, T-treason. You mean dat I betray -' The historian removed his glasses and wiped them with shaking hand, 'It's not true. You're trying to frighten me.'

'Oh, no, I'm not. Korsakoff thinks you know more than you're telling. He's sure that you're either holding out for a price or, more likely, that you've sold out to the Veenies.'

'But Doming -'

Thorning isn't any too secure himself. He has his own skin to think of. Earth governments in moments of stress are not famous for being reasonable.' There were sudden tears in his eyes, 'Ullen, there must be something you can do. It's not only you - it's for Earth.'

Ullen's breathing whistled harshly, 'Dey tink I would sell my scientific knowledge. Is dat de kind of insult dey pay my sense of eddies; my scientific integrity?' His voice was thick with fury and for the first time since Johnnie knew him, he lapsed into guttural Martian. 'For dat, I say not a word,' he finished. 'Let dem put me in prison or shoot me, but dis insult I cannot forget.'

There was no mistaking the firmness in his eyes, and Johnnie's shoulders sagged. The Earthman didn't move at the glare of the signal light.

'Answer de light, Johnnie,' said the Martian, softly, 'dey are coming for me.'

In a moment, the room was crowded with green uniforms. Dr. Thorning and the two with him were the only ones present in civilian clothes.

Ullen struggled to his feet, 'Gentlemen, say nodding. I have heard dat it is dought dat I am selling what I know - selling for money.' He spat the words. 'It is a ding never before said of me - a ding I have not deserved. If you wish you can imprison me immediately, but I shall say nodding more - nor have any-ding furder to do wid de Eard government.'

A green-garbed official stepped forward immediately, but Dr. Thorning waved him back.

'Whoa, there, Dr. Ullen,' he said jovially, 'don't jump too soon. I've just come to ask if there isn't a single additional fact that you remember. Anything, no matter how insignificant-'

There was stony silence. Ullen leant heavily on his crutches but remained stolidly erect.

Dr. Thorning seated himself imperturbably upon the historian's desk, picked up the high stack of type-written pages, 'Ah, is this the manuscript young Brewster was telling me about.' He gazed at it curiously, 'Well, of course, you realize that your attitude will force the government to confiscate all this.'

'Eh?'.Ullen's stern expression melted into dismay. His crutch slipped and he dropped heavily into his seat.

The physicist warded off the other's feeble clutch, 'Keep your hands off, Dr. Ullen, I'm taking care of this.' He leafed through the pages with a rustling noise. 'You see, if you are arrested for treason, your writings become subversive.'

'Subversive!' Ullen's voice was hoarse, 'Dr. Doming, you don't know what you are saying. It is my - my great labor.' His voice caught huskily, 'Please, Dr. Doming, give me my manuscript.'

The other held it just beyond the Martian's shaking fingers.

'If-'he said.

'But I don't know!'

The sweat stood out on the historian's pale face. His voice came thickly. 'Time! Give me time! But let me dink - and don't, please don't harm dis manuscript.'

The other's fingers sank painfully into Ullen's shoulder, 'So help me, I burn your manuscript in five minutes, if-'

'Wait, I'll tell you. Somewhere - I don't know where - it was said dat in de weapon dey used a special metal for some of de wiring. I don't know what metal, but water spoiled it and had to be kept away - also air. It -'

'Holy jumping Jupiter,' came the sudden shout from one of Thorning's companions. 'Chief, don't you remember Aspar-tier's work on sodium wiring in argon atmosphere five years ago-'

Dr, Thorning's eyes were deep with thought, 'Wait - wait -wait - Damn! It was staring us in the face -'

'I know,' shrieked Ullen suddenly. 'It was in Karisto. He was discussing de fall of Gallonie and dat was one of de minor causes - de lack of dat metal - and den he mentioned -'

He was talking to an empty room, and for a while he was silent in puzzled astonishment.

And then, 'My manuscript!' He salvaged it from where it lay scattered over the floor, hobbling painfully about, smoothing each wrinkled sheet with care.

'De barbarians - to treat a great scientific work so!'

Ullen opened still another drawer and scrabbled through its contents. He closed it and looked about peevishly, 'Johnnie, where did I put dat bibliography? Did you see it?'

He looked toward the window, 'Johnnie!'

Johnnie Brewster said, 'Wait a while, Ullen. Here they come now.'

The streets below were a burst of color. In a long, stiffly-moving line the Green of the Navy paraded down the avenue, the air above them snow-thick with confetti, hail-thick with ticker-tape. The roar of the crowd was dull, muted.