Vibulenus and his fellows had staggered off the lower end of the gangway, to the glassy remnants of the original siege ramp. At the tribune’s first step, his leg crunched through what had seemed to be firm ground. It was like walking through a crusted snowdrift, except that the edges drew blood as they scraped Vibulenus’ calf.
The gallery dipped forward as other Romans broke through as well. The fire had consumed everything flammable in the siegeworks; but wherever there was enough silica in the earth to vitrify, glass had kept the fill from setting under its own weight and the heavy rains. The sprawled remnants were not impassible, but they provided a barrier of hidden pits covering half of the last twenty feet between the new ramp and the base of the tower.
And that saved the lives of the men in the gallery.
The defenders were expert in their use of flame, so expert that the first gout of blazing fluid travelled from the spout with the conflicting pulls of gravity and outward inertia in an arc calculated to splash it under the roof of the gallery. The autochthones knew that by flooding the area when the assault force was directly beneath, they could destroy the legionaries as completely as they had the first siege ramp — but there was no need to runnel flame over the refractory roof of the gallery if the clinging, erosive liquid could be splashed onto the legs of the men inside.
The gallery wobbled to a halt three feet short of where the defenders expected it when they started their flame on its long fall.
Vibulenus’ calves itched in a way that was more intrusive than any pain could be. Sweat that raced down his thighs paused and burned when it reached the grit and abrasions on his lower legs. He could not take a hand from the bar he carried to scratch the affected area. His palms were hot and the skin of them, though calloused by swordhilt and shield strap, slipped over the muscle and bone beneath. The unusual stress of carrying the gallery was reducing his hands to puffy, bleeding blisters.
The tribune could see only dimly. The assault force was in an artificial valley between the siege ramp and the sheer wall of the tower. Most of what sunlight did scatter through was blocked by the sheltering roof, and even the remainder was blurred by the sweat and tears which Vibulenus could not wipe away. The tumbling flame, striking and splashing before the gallery, instantly returned light and color to a microcosm of gray pain.
“Mother!” screamed Clodius, loud enough for the tribune to hear him and be surprised. Everybody was shouting, though, and the flames roared as they splattered and eroded the earth. The fire was deep red, with flecks of quicklime as white as rage and a shroud of ragged smoke that was visible only at a distance from the bubbling flame.
The gallery grounded before anyone had the presence of mind to order it down. Hands dropped the bars in panic as the men of the assault force tried to jump back. They tangled themselves with the structure and the men behind them.
A legionary in the fifth row did manage to leap out the rear of the shelter. Sunlight and the imprisoning hugeness of the structures before and behind drove the man back under the roof of a moment later. He brushed off his helmet on the eaves. As it rolled on the blackened rubble, a dozen quarrels snapped toward and clangingly against it.
“All right,” ordered Gaius Vibulenus. His voice was as cool as the core of him which shock had disconnected from the sweating, punished body he wore. Clodius Afer and the other men in the front rank were being burned by the pool of fire which closed their end of the gallery, and the tribune’s own shins were scorching. “We’re going to side-step left, now. Take your bars and lift!”
He should have worn his greaves . . . and he was so disoriented that he almost failed to obey the orders he had given the men who were suddenly under his actual control.