'I understand.' larhai's mouth was a thin line, like the mouth of a fish. 'I will not trouble you further. I have to do the rounds of my men. Come, daughter.'
Bathshiba got down from the wall. As they made their formal farewells, Ballista could read nothing in her face.
Calgacus appeared and led them out.
Ballista leant on the wall and looked out into the night. On silent wings an owl was hunting over the big island. Again he heard the bark of a fox, nearer now. There was a light footstep behind him. He turned fast, his hand going to his sword. Bathshiba stood there, just out of reach.
'That was not my idea,' she said.
'I did not think that it was.' They looked at each other in the pale moonlight.
'I am worried about my father. He is not himself. The fight has gone out of him. He hardly ever goes to the battlements. He leaves everything to do with the troops to Haddudad. He stays in his rooms. If you ask him his opinion about anything he just says that it will be as god wills. You must have seen. He is even being nice about Anamu and Ogelos.'
Ballista took a step towards her.
'No. My father is waiting at the gate. I left something.' She walked around Ballista and picked up her cap from the wall. She pushed it on her head, piling her long black hair under it. 'I must go.' She smiled and left.
Back sitting on the wall, Ballista took the amulet from his purse and turned it in his hands. MILES ARCANUS – literally secret or silent soldier. It was the mark of a frumentarius.
Ballista was sweating like a Christian in the arena. The air was very bad down here, close and fetid. It was hard to draw breath properly. At Mamurra's gesture, the northerner moved at a crouch to the far right of the gallery. The sweat was slick on his sides. Kneeling down, he put his ear to the first of the round shields held to the wall. The bronze was cold to his ear. He listened. He would have liked to shut his eyes to concentrate on listening, but he feared what would happen when he opened them again. He had done that once before, and he had no wish to relive that almost physical surge of panic that ran up through his body as his eyes told him that he was still in the tunnel.
After a time he looked at Mamurra and shook his head. He could hear nothing. Mamurra gestured to the next shield. His fear making him clumsy, Ballista shuffled along and put his ear to this one. He put his hand over his other ear. He tried to calm himself, tried to filter out the thumping of his heart, the small scratching noises as the shield moved imperceptibly against the rock. Yes, now he thought he heard something. He listened some more. He was not sure. He made a gesture of uncertainty, palms up. Mamurra pointed to the final shield. With this one there was no doubt. There it was: the steady, rhythmic chink, chink, chink of pickaxe on stone.
Ballista nodded. Mamurra pointed, his hand describing an arc from straight ahead to about forty-five degrees off to the left. Then, still without speaking, he held out the splayed fingers of his right hand, once, twice, three times. The enemy mine was approaching from the left; it was about fifteen paces away. Ballista nodded and jerked his head towards the entrance. Mamurra nodded back. Still crouching, Ballista turned to leave, hoping his pathetic relief was not too evident.
Back above ground, back from the realm of the dead, Ballista sucked air into his lungs. The hot, gritty, dust-laden air that hung over the town of Arete was like the coldest, cleanest air off the northern ocean of his childhood. Gulping it down, he used his scarf to mop the stinging sweat and dirt from his eyes. Maximus passed him a skin for water. He cupped a hand, filled it and bathed his face. Above him, the wind sail over the entrance to the mine hung limp. One of Mamurra's engineers was tipping a bucket of water over it to try and make it draw better.
'Now I can show it to you from up above,' said Mamurra.
In contrast to what had gone before, the view from the battlements of the south-west tower was Olympian. There off to the right was what remained of the Persian siege ramp. Broken-backed, it lay like a stranded whale. Beyond it was the broad sweep of the plain. Shattered missiles, scraps of clothing and bleached bones broke the wide, dun-coloured monotony that stretched all the way to the Sassanid camp.
They kept low behind the much-repaired parapet. Since the fall of the ramp shooting had been desultory, but a man in full view would still attract missiles. Mamurra borrowed a bow from one of the sentinels. He selected an arrow with bright fletching. He looked round the crenellations to find his mark, ducked back into cover, took a deep breath and stepped out to draw and release. Ballista noted that Mamurra drew the bowstring not with two fingers but with his thumb, like the nomads of the steppes.
'Hmm.' Mamurra grunted as the arrow embedded itself in the ground, its bright red feathers quivering. He considered for a moment or two. 'You see the arrow? Now move your eyes five paces to the right. Now almost ten paces away. Not as far as the scrap of yellow material. You see what looks like a large molehill?' Ballista saw it. 'Now move further away, twenty-five, thirty paces. You see the next one? Then, at a similar distance, the one beyond that?'
'I see them. That was not a great shot,' Ballista said.
'I have done better.' Mamurra grinned. 'It served its purpose. Now you can see the air shafts the reptiles have dug up from their mine. The Persian tunnel is considerably longer than ours so those air shafts are necessary. Ours is about forty paces long. Much further and the air gets bad at the head of the mine. The wind sail helps a little. If there had been time I would have dug another tunnel next to our mine: if you light a fire at the mouth of a parallel tunnel it draws out the bad air.'
Allfather, but he is a good siege engineer this one, a good Praefectus Fabrum. I am lucky to have him.
'I think that their tunnel will pass just to the left of our cross gallery. We will have to dig a little more to catch them,' Mamurra continued in answer to Ballista's unspoken question. 'There is a risk that they will hear us digging, that they will be ready for us. But we will dig and listen by turns. Anyway, it cannot be helped.'
Both were silent. Ballista wondered if Mamurra was also thinking that the traitor might already have warned the Sassanids of the Roman counter mine.
'When you intercept them, what will you do?'
As was often his way, Mamurra slowly mulled the question over. 'We could try and break into their tunnel from below, light a fire and smoke them out. Or we could come in from above, throw down missiles, maybe pour in boiling water, try to make their mine unworkable. But neither really answers. As I told the Greek boy when he talked of bears, bees, scorpions and such things, it will be nasty work in the dark with a short sword.'
'And then?'
'Collapse their mine. Preferably not with us still in it.'
'How many men will you need?'
'Not many. Numbers can be an encumbrance underground. When I ask, bring up the reserve century stationed on the campus martius. I will take twenty of them into the tunnel to add to my miners. Have the rest of the century around the entrance. Keep Castricius with you, in case things should work out badly.' The corners of Mamurra's mouth were turned down.
'I will tell the centurion Antoninus Posterior to have his men ready.'
Two days passed before a red-faced messenger sought out the Dux Ripae. Ballista collected Antoninus Posterior and his men. When they reached the mine Mamurra was waiting. There was no time for an extended farewell. Ballista shook the hand of his praefectus fabrum, and Mamurra led twenty legionaries into the tunnel.