move. There are no really new principles in modern warfare, you know; merely new methods of applying the old principles. Medieval man knew all the principles.’
He looked glumly at his empty pipe. ‘They had a variety of weapons. The onager is no use for our purpose, of course. I did think of the mangonel and the ballista, but I discarded those too, and finally settled on the trebuchet. Powered by gravity, you know, and very effective.’
If the crossbows had not been such a great success O’Hara would have jeered at Armstrong, but now he held his peace, contenting himself with looking across at Forester ironically. Forester still looked baffled and shrugged his shoulders. ‘What sort of missile would the thing throw?’ he asked.
‘I was thinking of rocks,’ said Armstrong. ‘I explained the principle of the trebuchet to Willis and he has worked it all out. It’s merely the application of simple mechanics, you know, and Willis has got all that at his fingertips. We’ll probably make a better trebuchet than they could in the Middle Ages – we can apply the scientific principles with more understanding. Willis thinks we can throw a twenty-pound rock over a couple of hundred yards with no trouble at all.’
‘Wow!’ said O’Hara. He visualized a twenty-pound boulder arching in a high trajectory – it would come out of the sky almost vertically at that range. ‘We can do the bridge a bit of no good with a thing like that.’
‘How long will it take to make?’ asked Forester.
‘Not long,’ said Armstrong. ‘Not more than twelve hours, Willis thinks. It’s a very simple machine, really.’
O’Hara felt in his pocket and found his cigarette packet. He took one of his last cigarettes and gave it to Armstrong. ‘Put that in your pipe and smoke it. You deserve it.’
Armstrong smiled delightedly and began to shred the cigarette. ‘Thanks,’ he said. ‘I can think much better when I smoke.’
O’Hara grinned. ‘I’ll give you all my cigarettes if you can come up with the medieval version of the atom bomb.’
‘That was gunpowder,’ said Armstrong seriously. ‘I think that’s beyond us at the moment.’
‘There’s just one thing wrong with your idea,’ O’Hara commented. ‘We can’t have too many people up at the camp. We must have somebody down at the bridge in case the enemy does anything unexpected. We’ve got to keep a fighting force down here.’
‘I’ll stay,’ said Armstrong, puffing at his pipe contentedly. ‘I’m not very good with my hands – my fingers are all thumbs. Willis knows what to do; he doesn’t need me.’
‘That’s it, then,’ said O’Hara to Forester. ‘You and Miguel go up to the camp, help Willis and Peabody build this contraption, then push on to the mine tomorrow. I’ll go down and relieve Willis at the bridge.’
III
Forester found the going hard as they climbed up to the camp. His breath wheezed in his throat and he developed slight chest pains. Rohde was not so much affected and Willis apparently not at all. During the fifteen-minute rest at the halfway point he commented on it. ‘That is acclimatization,’ Rohde explained. ‘Señor Willis has spent much time at the camp – to come down means nothing to him. For us going up it is different.’
‘That’s right,’ said Willis. ‘Going down to the bridge was like going down to sea-level, although the bridge must be about twelve thousand feet up.’
‘How high is the camp?’ asked Forester.
‘I’d say about fourteen and a half thousand feet,’ said Willis. ‘I’d put the mine at a couple of thousand feet higher.’
Forester looked up at the peaks. ‘And the pass is nineteen thousand. Too close to heaven for my liking, Miguel.’
Rohde’s lips twisted. ‘Not heaven – it is a cold hell.’
When they arrived at the camp Forester was feeling bad and said so. ‘You will be better tomorrow,’ said Rohde.
‘But tomorrow we’re going higher,’ said Forester morosely.
‘One day at each level is not enough to acclimatize,’ Rohde admitted. ‘But it is all the time we can afford.’
Willis looked around the camp. ‘Where the hell is Peabody? I’ll go and root him out.’
He wandered off and Rohde said, ‘I think we should search this camp thoroughly. There may be many things that would be of use to O’Hara.’
‘There’s the kerosene,’ said Forester. ‘Maybe Armstrong’s gadget can throw fire bombs. That would be one way of getting at the bridge to burn it.’
They began to search the huts. Most of them were empty and disused, but three of them had been fitted out for habitation and there was much equipment. In one of the huts they found Willis shaking a recumbent Peabody, who was stretched out on a bunk.
‘Five arrows,’ said Willis bitterly. ‘That’s all this bastard has done – made five arrows before he drank himself stupid.’
‘Where’s he getting the booze?’ asked Forester.
‘There’s a case of the stuff in one of the other huts.’
‘Lock it up if you can,’ said Forester. ‘If you can’t, pour it away – I ought to have warned you about this, but I forgot. We can’t do much about him now – he’s too far gone.’
Rohde who had been exploring the hut grunted suddenly as he took a small leather bag from a shelf. ‘This is good.’
Forester looked with interest at the pale green leaves which Rohde shook out into the palm of his hand. ‘What’s that?’
‘Coca leaves,’ said Rohde. ‘They will help us when we cross the mountain.’
‘Coca?’ said Forester blankly.
‘The curse of the Andes,’ said Rohde. ‘This is where cocaine comes from. It has been the ruin of the indios – this and aguardiente. Señor Aguillar intends to restrict the growing of coca when he comes into power.’ He smiled slowly. ‘It would be asking too much to stop it altogether.’
‘How is it going to help us?’ asked Forester.
‘Look around for another bag like this one containing a white powder,’ said Rohde. As they rummaged among the shelves, he continued, ‘In the great days of the Incas the use of coca was restricted to the nobles. Then the royal messengers were permitted to use it because it increased their running power and stamina. Now all the indios chew coca – it is cheaper than food.’
‘It isn’t a substitute for food, is it?’
‘It anaesthetises the stomach lining,’ said Rohde. ‘A starving man will do anything to avoid the pangs of hunger. It is also a narcotic, bringing calmness and tranquillity – at a price.’
‘Is this what you’re looking for?’ asked Forester. He opened
