Allen felt a cold constriction about his windpipe as he stared about him quickly. Things looked different in semi-darkness, but they looked more different than they ought. It was impossible for things to be so different.

'We should've sighted Old Baldy by now, shouldn't we have?' he quavered.

'We sh'd've sighed him long ago,' came the hard answer. ' 'Tis that domned quake. Landslides must've changed the trails. The peaks themselves must've been screwed up -' His voice was thin-edged, 'Allen, 'tisn't any use making believe. We're dead lost.'

For a moment, they stood silently - uncertainly. The sky was purple and the hills retreated into the night. Allen licked bluechilled lips with a dry tongue.

'We can't be but a few miles away. We're bound to stumble on the city if we look.'

'Consider the situation, Airthman,' came the savage, shouted answer, ' 'Tis night, Martian night. The temperature's down past zero and plummeting every minute. We haven't any time t' look; - we've got t' go straight there. If we're not there in half an hour, we're not going t' get there at all.'

Allen knew that well, and mention of the cold increased his consciousness of it. He spoke through chattering teeth as he drew his heavy, fur-lined coat closer about him.

'We might build a fire!' The suggestion was a half-hearted one, muttered indistinctly, and fallen upon immediately by the other.

'With what?' George was beside himself with sheer disappointment and frustration. 'We've pulled through this far, and now we'll prob'ly freeze t' death within a mile o' the city. C'mon, keep running. It's a hundred-t'-one chance."

But Allen pulled him back. There was a feverish glint in the Earthman's eye, 'Bonfires!' he said irrelevantly. 'It's a possibility. Want to take a chance that might do the trick?'

'Nothin' else t' do,' growled the other. 'But hurry. Every minute I -'

'Then run with the wind - and keep going.'

'Why?'

'Never mind why. Do what I say - run with the wind!'

There was no false optimism in Allen as he bounded through the dark, stumbling over loose stones, sliding down declivities, - always with the wind at his back. George ran at his side, a vague, formless blotch in the night.

The cold was growing more bitter, but it was not quite as bitter as the freezing pang of apprehension gnawing at the Earthman's vitals.

Death is unpleasant!

And then they topped the rise, and from George's throat came a loud 'B' Jupe 'n' domn!' of triumph.

The ground before them, as far as the eye could see, was dotted by bonfires. Shattered Aresopolis lay ahead, its homeless inhabitants making the night bearable by the simple agency of burning wood.

And on the hilly slortes, two weary figures slapped each other on the backs, laughed wildly and pressed half-frozen, stubbly cheeks together for sheer, unadulterated joy.

They were there at last!

The Aresopolis lab, on the very outskirts of the city, was one of the few structures still standing. Within, by makeshift light, haggard chemists were distilling the last drops of extract.

Without, the city's police-force remnants were clearing desperate way for the precious flasks and vials as they were distributed to the various emergency medical centres set up in various regions of the bonfire-pocked ruins that were once the Martian metropolis.

Old Hal Vincent supervised the process and his faded eyes ever and again peered anxiously into the hills beyind, watching hopefully but doubtfully for the promised cargo of blooms.

And then two figures reeled out of the darkness and collapsed to a halt before him.

Chill anxiety clamped down upon him, 'The blooms! Where are they? Have you got them?'

'At Twin Peaks,' gasped Allen. 'A ton of them and better in a sand-truck. Send for them.'

' A group of police grind-cars set off before he had finished, and Vincent exclaimed bewilderedly, 'A sand-truck? Why didn't you send it in a ship? What's wrong with you out there, anyway? Earthquake-'

He received no direct answer. George had stumbled toward the nearest bonfire with a beatific expression on his worn face.

'Ahhh, 'tis warm!' Slowly, he folded and dropped, asleep before he hit the ground.

Allen coughed gaspingly, 'Huh! The Gannie tenderfoot! Couldn't - ulp - take it!'

And the ground came up and hit him in the face.

Allen woke with the evening sun in his eyes and the odor of frying bacon in his nostrils. George shoved the frying pan toward him and said between gigantic, wolfing mouthfuls, 'Help yourself.',

He pointed to the empty sand-truck outside the labs, 'They got the stuff all right.'

Allen fell to, quietly. George wiped his lips with the back of his hand and said, 'Say, All'n, how 'd y' find the city? I've been sitting here trying t' figure it all out.'

'It was the bonfires,' came the muffled answer. 'It was the only way they could get heat, and fires over square miles of land create a whole section of heated air, which rises, causing the cold surrounding air of the hills to sweep in.' He suited his words with appropriate gestures. 'The wind in the hills was heading for the city to replace warm air and we followed the wind. - Sort of a natural compass, pointing to where we wanted to go.'

George was silent, kicking with embarrassed vigor at the ashes of the bonfire of the night before.

'Lis'n, All'n, I've had y" a'wrong. Y' were an Airthman tanderfoot t' me till-' He paused, drew a deep breath and exploded with, 'Well, by Jupe 'n' domn, y'r my twin brother and I'm.proud o' it. All Airth c'dn't drown out the Carter blood in y'.'

The Earthman opened his mouth to reply but his brother clamped one palm over it. 'Y' keep quiet, till I'm finished. After we get back, y' can fix up that mechanical picker or anything else y' want. I drop my veto. If Airth and machines c'n tairn out y'r kind o' man, they're all right. But just the same,' there was a trace of wistfulness in his voice, 'y' got t' admit that everytime the machines broke down - from irrigation-trucks and rocket-ships to ventilators and sand-trucks -'twas men who had t' pull through in spite o' all that Mars could do.'

Allen wrenched his face from out behind the restraining palm.

The machines do their best,' he said, but not too vehemently.

'Sure, but that's all they can do. When the emairgency comes, a man's got t' do a damn lot better than his best or he's a goner.'

The other paused, nodded and gripped the other's hand with sudden fierceness, 'Oh, we're not so different. Earth and Ganymede are plastered thinly over the outside of us, but inside -'

He caught himself.

'Come on, let's give out with that old Gannie quaver.'

And from the two fraternal throats tore forth a shrieking eldritch yell such as the thin, cold Martian air had seldom before carried.

 I got the cover again with 'Heredity.'

 In connection with that story, I remember best a comment I received from a young fellow named Scott Feldman (who was then still in his teens but who was later, as Scott Meredith, to become one of the most important literary agents in the business). He disapproved of the story because I introduced two characters at the start who disappeared from the story and were never heard of again.

 Once that was pointed out to me, it seemed to me that this was indeed a major flaw, and I wondered why neither Campbell nor Pohl had specifically pointed it out. I never quite had the courage to ask, however.

 But it did cause me to look at my stories more closely thereafter, and to realize again that writing isn't all inspiration and free flow. You do have to ask yourself pretty mechanical questions, such as, 'What do I do with this character now that I've taken the trouble to make use of him?'