Pompeii

admiral's shoulders, then Attilius jumped down in a shower of pumice, and finally Torquatus, slamming the trap behind them.

Vespera

    [20:02 hours]

'During [the first] phase the vent radius was probably of the order of 100 metres. As the eruption continued, inevitable widening of the vent permitted still higher mass eruption rates. By the evening of the 24th, the column height had increased. Progressively deeper levels within the magma chamber were tapped, until after about seven hours the more mafic grey pumice was reached. This was ejected at about 1.5 million tonnes per second, and carried by convection to maximum heights of around 33 kilometres.'
Volcanoes: A Planetary Perspective

    In the stifling heat and the near-darkness beneath the Minerva 's decks they crouched and listened to the drumming of the stones above them. The air was rank with the sweat and breath of two hundred sailors. Occasionally, a foreign voice would cry out in some unrecognisable tongue only to be silenced by a harsh shout from one of the officers. A man near Attilius moaned repeatedly in Latin that it was the end of the world – and that, indeed, was what it felt like to the engineer. Nature had reversed herself so that they were drowning beneath rock in the middle of the sea, drifting in the depths of night during the bright hours of the day. The ship was rocking violently but none of the oars was moving. There was no purpose to any activity for they had no idea of the direction in which they were pointing. There was nothing to do but endure, each man huddled in his own thoughts.
    How long this went on, Attilius could not calculate. Perhaps one hour; perhaps two. He was not even sure where he was below decks. He knew that he was clinging to a narrow wooden gantry that seemed to run the length of the ship, with the double-banks of sailors crammed on benches on either side. He could hear Pliny wheezing somewhere close, Alexion snuffling like a child. Torquatus was entirely silent. The incessant hammering of the pumice fall, sharp to begin with as it rattled on the timber of the deck, gradually became more muffled, as pumice fell on pumice, sealing them off from the world. And that, for him, was the worst thing – the sense of this mass slowly pressing down on them, burying them alive. As time passed he began to wonder how long the joists of the deck would hold, or whether the sheer weight of what was above them would push them beneath the waves. He tried to console himself with the thought that pumice was light: the engineers in Rome, when they were constructing a great dome, sometimes mixed it into the cement in place of rock and fragments of brick. Nevertheless he gradually became aware that the ship was starting to list and very soon after that a cry of panic went up from some of the sailors to his right that water was pouring through the oar-holes.
    Torquatus shouted at them roughly to be quiet then called down the gantry to Pliny that he needed to take a party of men above decks to try to shovel off the rock-fall.
    'Do what you have to do, captain,' replied the admiral. His voice was calm. 'This is Pliny!' he suddenly bellowed above the roar of the storm. 'I expect every man to bear himself like a Roman soldier! And when we return to Misenum, you will all be rewarded, I promise you!'
    There was some jeering from the darkness.
    'If we return, more like!'
    'It was you who got us into the mess!'
    'Silence!' yelled Torquatus. 'Engineer, will you help me?' He had mounted the short ladder to the trapdoor and was trying to push it open but the weight of the pumice made it hard to lift. Attilius groped his way along the gantry and joined him on the ladder, holding on to it with one hand, heaving with the other at the wooden panel above his head. Together they raised it slowly, releasing a cascade of debris that bounced off their heads and clattered on to the timbers below. 'I need twenty men!' ordered Torquatus. 'You five banks of oars – follow me.'
    Attilius climbed out after him into the whirl of flying pumice. There was a strange almost brownish light, as in a sandstorm, and as he straightened Torquatus grabbed his arm and pointed. It took Attilius a moment to see what he meant, but then he glimpsed it too – a row of winking yellow lights, showing faintly through the murk. Pompeii, he thought – Corelia!
    'We've drifted beneath the worst of it and come in close to the coast!' shouted the captain. 'The gods alone know where! We'll