"The tunnels are nearly three feet long by this time, Señor. It takes about an hour to cut away a foot." "Any sound of the French?" "None, Señor." "Very well. Another four feet will finish these. But we mustn’t stop at that. We can’t hope to keep the enemy back altogether by one explosion at those walls. It would delay them, certainly, and do considerable damage; but we’ll have to prepare to give them much more trouble farther back." "I had thought of that, Señor." "Well, I think we’ll go and have a look at the cellars. Come along. Bring your measure with you; we shall require that, and a candle." Descending to the cellars of the Casa Alvarez, Jack found that they ran along the walls on the west and north sides of the building, at a distance of ten feet below the surface of the ground. They formed a series of arched rooms leading one from the other, with small openings for ventilation giving on the patio. "Dark musty places these!" said Jack. "Judging by the appearance of them, they haven’t been used for a century. There’s not even a bottle of wine to be seen, let alone a rat. Ah! I spoke too soon; sh-h-h!" A rat had just scurried along the wall into its hole in the corner. "I have been thinking over things," resumed Jack, "and I shall be glad of your opinion of the plan I have partly formed. Our object, of course, must be to hold the French in check as long as possible; but if they succeed in occupying the two houses opposite, and the Casa Vallejo, we shall be very hard put to it to defend the plaza and this house. They outnumber us. It is quite likely that, in spite of all we can do, they will eventually succeed in obtaining a lodgment in these three houses or their ruins. I propose, therefore, to plan our defence on the assumption that they will do so. This house in which we now stand will be our fort, and we should arrange so that we can do the enemy as much damage as possible from this spot." "That is reasonable, Señor," said Don Cristobal. "Well, the greatest damage we can do will be done by mines like their own—either to destroy their mines before they have time to explode them, or to drive the enemy back when they have exploded their mines and seized the houses. To do that effectually we require to drive at least two galleries from these cellars under each house. But the Casa Vallejo is too far away. We haven’t men enough, and it would take too long, to cut a gallery from here right across the plaza and street and under that house. The Casas Vega and Tobar are much nearer, and I see nothing to prevent us from cutting the galleries under them." "In addition to the short tunnels already being cut under the party-walls?" asked Don Cristobal. "Oh yes! You see my aim? The short tunnels are to delay their attack on those houses; the longer tunnels I propose are to check their advance on this house when they have captured the others." "But why two long galleries, Señor?" asked Pulgar.