It still wanted some minutes of dawn when his motley force was drawn up in the plaza behind the walls of Vega and Tobar. It numbered only 350 men in all—some haggard burghers of the city, some rugged guerrilleros from the country districts, a few regulars from General Fiballer's Valencian regiment, a few of Palafox's grenadiers. All bore signs of the stress and toil of the past few weeks; but all were animated by one spirit of indomitable resolution. Fifty of the best marksmen were at once picked out to garrison Tobar and Vallejo and harass the French with musketry-fire from the windows. Eighty good men were drafted as a reserve. This left 220, of whom 120 were told off to make the main sortie over the barricade in the street between Tobar and Vallejo, while 30 were appointed to guard the shorter barricade across the lane between Tobar and Vega. The remaining 70 were ordered to march to the upper side of the Casa Vega and make a demonstration at the barricade erected in the street there.

Jack had resolved to lead the principal sortie in person, and he devoted special attention to the organization of his band. Ten of the men were ordered to carry bags of powder to blow up the French galleries into Tobar and Vallejo, if the sortie party were able to push home their charge. Another ten were given short ladders and mats to assist the rest across the barricade, which was of timber, some twelve feet in height, and studded at the top with sharp nails. It had been constructed so hastily, and with so little idea of the possibility of a sortie, that it formed almost as formidable an obstacle to the Spaniards as to the French.

The sortie party beyond the Casa Vega was entrusted to Don Cristobal, the reserve to Pablo Quintanar, the chief of the guerrilleros. This man was very much dissatisfied with the post allotted him; he grumbled and protested that he deserved a more prominent part in the operations, but Jack had a vague distrust of the fellow, and somewhat curtly refused to alter his arrangements.

All was now ready. In the chill foggy dawn the men waited at their several posts for the expected explosion. Sounds floated across the river from the French lines: the blare of bugles, the rat-tat of drums, occasionally the loud call of bustling officers. Jack began to wonder whether the French would wait until their galleries into Tobar and Vallejo were ready, and then spring the three mines simultaneously. But the anxious period of waiting was at length ended. About an hour after daybreak there was a dull roar; the whole district seemed to tremble; there was the crash of falling stones and timber, a cloud of smoke and dust from the Casa Vega, and with a shout the French rushed into the ruined building beyond, to make good their position there.

Then came a terrible interval of suspense, even more trying to the nerves of the Spaniards than the long wait for the French explosion. When would they hear the answering explosion? Had the gallant fellow who had offered to fire the train perished before his work was done? Jack wondered, waited anxiously. Second after second slipped by; he could hear the ticking of the watch in his vest pocket. At last when, unable to endure the uncertainty longer, he was about to rush into the casa himself, a deafening noise like a thunderclap close at hand checked him. The French mine, acting immediately upon the wall and at a considerable depth below-ground, had spent most of its force on the wall itself. But Jack's mine, having only a few feet of earth above it, and being heavily charged, exerted its destructive effect in all directions. It blew to fragments the ruins of the house adjoining the Casa Vega, brought down what remained of its roof, shattered the remnants of the walls on either side, and filled the air for a hundred yards around with dust and débris, a few of Jack's men, even in the plaza behind, being injured by objects that were shot clean over the houses. Jack, from his position, could not see the extent of the damage; but the fact that the explosion had actually occurred left him in no doubt that the French in the ruined house beyond the Casa Vega must have been annihilated, and in the ruins, where they had but slight protection, they must have suffered heavy loss.

But he hardly waited to estimate the effect of his successful coup. Immediately after the explosion he gave his men the order to advance; they dashed from cover and began to swarm over the barricades. At the last moment Jack sent a man with orders to barricade as far as possible the newly-made breach in the Vega wall. Then, with Antonio at his side, he led the charge. The dust was still falling in clouds as they came to the Tobar barricade. So sudden was the unexpected event, and so swiftly did the Spaniards move, that their manoeuvre was not discovered by the French until the greater number had crossed and, headed by Jack and Antonio, charged down the street. But within fifty paces a shot rang out from beyond the ruined house on their left; it was followed immediately by a scattered fire, and amid yells of rage and pain many of Jack's men fell. The French were firing from the half-dismantled houses they had rushed a few days before, which, being somewhat remote from the scene of the explosion, and sheltered by the ruins of the house adjoining the Casa Tobar, had not suffered like the rest of the French position. Nothing daunted by their losses, the Spaniards pressed on with shouts of "Nuestra Señora del Pillar! A la cuchillo!" Don Cristobal meanwhile had swept round the upper barricade. The ruins beyond the houses lately burnt were carried with a rush. Drums were heard beating not far away; there were loud shouts in French and the hurried tramp of feet. It was clear that the enemy, not anticipating danger at this point, had drawn away their troops in the direction of the Franciscan convent; they had expected that under cover of the explosion the Casa Vega would be captured, as a score of houses in the same quarter had been rushed before, by a handful of disciplined men. No plans had been made to meet so unexpected a movement of retaliation; for a moment the battle was to the Spaniards.

But Jack knew well that he durst not attempt to push his attack far. He had given orders to Antonio, who had led a small body to the assault of a house to the left, where the street bent inwards from the ramparts, to blow up the head of the gallery into the Casa Vallejo, then to retire towards that house, recross the barricade, and take up a position behind it. To cover these movements, Jack directed a party of his men to keep up a hot fire on the house at the bend of the street, from which some French marksmen had swept the front of the attacking force. Within a few minutes he heard a sharp report. At the same time Antonio's men came streaming back towards Vallejo and over the barricade. One of the French galleries was evidently accounted for.

Meanwhile Jack's own position had been hotly assailed in front. The ruined houses on the right of the street were now full of Frenchmen, who charged again and again across the débris up to the party-wall, only to be driven back by the men stationed there, under such cover as the irregular remnants of the broken walls afforded. There was no time to barricade the gap; it was only a question of time before the French must break through in overwhelming numbers. Don Cristobal had occupied the ruins adjoining the Casa Vega, but he was now ordered back across his barricade, from which he could protect the flank of Jack's force when it became necessary to withdraw it.

At this juncture Jack felt the necessity of obtaining a view of the whole position. He looked round for some point of observation. Through a large rent in one of the walls to his right he perceived the remains of a staircase to the second story. Was there time to clamber up it before the French burst in? "I'll chance it," he said to himself. Ordering his men to stand firm, he ran across the narrow lane, through the wall, and began to ascend the staircase. It was a rickety structure; its top had been blown away; it remained upright only by favour of one or two stout joists which had been so firmly embedded in the stone as to withstand the shock of the explosion when the party-wall was cracked. Up he went. The stairs creaked under him; at every step it seemed that the whole structure would fall with him. But at length he reached a spot whence, through a hole in what had been once the wall, he could see for a considerable distance over the quarter occupied by the French. To his left he saw the dreary waste of ruins through which, by patient mining and sudden rushes, the French had made their painful way from the convent of Santa Engracia, which stood a woful spectacle of destruction some hundreds of yards distant.

Eastward he traced their progress through a series of dismantled buildings, up to within a short distance of the Franciscan convent. Farther to the right they had made yet deeper inroads into the city, and were now almost within arm's-length of the Coso. Jack thought, with a sudden pang, of the danger Juanita would soon be in, and decided that at the earliest opportunity he must persuade her to change her quarters and retire northwards, loth as he was to see her in that fever-haunted spot.