As the day wore on, Jack found that the tunnelling proceeded more rapidly than he had expected. Working on a more definite plan than hitherto, the men saw that their chances of seriously checking the French advance were much greater, and dug and carried with a dogged perseverance that gave Jack a new respect for the Spanish character. By the evening the short holes under the party-walls nearest the French were ready for the charges. Thinking it advisable to see for himself what had been done, Jack crawled through one of the tunnels with a lighted candle, feeling the oppression of the dank confined air. He saw by the dim light that the sides and roof were roughly shored up with timber, and that, as he had wished, there was a slight slope upwards, so that the head of the tunnel was only about four feet from the surface. At the end he listened for the sound of the French miners, who, he guessed, were approaching, but hearing nothing concluded that they were not as yet so far advanced with their work. Returning to the rear end of the tunnel, he arranged for a heavy charge of powder to be placed in position with the fuses. When this had been done it was time to "tamp" the tunnels—fill them up again with earth to a distance greater than the depth of the mines below the surface. This was necessary, or when the explosion took place it would exhaust its force along the open tunnel instead of in the upward direction intended. But Jack decided not to do any tamping until he was sure that the French had driven their galleries so close to his own that the explosion of his own mines would destroy the enemy’s. If he found that the French tunnels were to the right or left of his own, so far away that his explosion would not greatly affect them, he would have to await the French explosion and then use his own mines to repel the attack on the buildings that would instantly follow. Late at night Antonio the guerrillero, who had been one of the most enthusiastic of the workers, reported that at the farther end of the short tunnel into the Casa Vega he had heard the faint sound of picks. Jack instantly crawled into the tunnel to listen for himself. Undoubtedly the man was right. Giving orders that men should take turns to watch all through the night at the tunnel head, he went to bed after midnight, tired out with the day’s exertions.