Lieutenant Ribouville now set to work to inspect the bridge; and ordered the men--who were provided with the necessary implements--to set to, and dig a hole down to the crown of the principal arch. It was harder work than they had expected. The roadway was solid, the ballast pressed down very tightly, and the crown of the arch covered, to a considerable depth, with concrete. Only a few men could work at once and, after a half-hour's desperate labor, the hole was nothing like far enough advanced to ensure the total destruction of the bridge, upon the charge being fired. In the meantime the Prussian sentries were arriving from up and down the line and, although not in sufficient force to attack, had opened fire from a distance.
"Don't you think that will do, Ribouville?" Major Tempe asked.
"No, sir," the other replied. "It might blow a hole through the top of the arch, but I hardly think that it would do so. Its force would be spent upwards."
At this moment Ralph--who had done his spell of work, and had been down to the stream, to get a drink of water--came running up.
"If you please, Lieutenant Ribouville, there is a hole right through the pier, just above the water's edge. It seems to have been left to let any water that gets into the pier, from above, make its escape. I should think that would do to hold the charge."
"The very thing," Lieutenant Ribouville said, delightedly. "What a fool I was, not to have looked to see if such a hole existed!
"Stop work, men, and carry the barrels down to the edge of the water."
The stream was not above waist deep; and the engineer officer immediately waded into it, and examined the hole. He at once pronounced it to be admirably suited to the purpose. It did not--as Ralph had supposed--go straight through; but there were two holes, one upon each side of the pier, nearly at the same level, and each extending into the center of the pier. The holes were about four inches square.
The barrels of gun cotton were now hastily opened on the bank, and men waded out with the contents. Lieutenant Ribouville upon one side, and Ralph upon the other, took the cotton and thrust it, with long sticks, into the ends of the hole. In five minutes the contents of the two barrels were safely lodged, the fuse inserted, and the operation of tamping--or ramming--in dry sand, earth, and stones commenced.
"Make haste!" Major Tempe shouted. "Their numbers are increasing fast. There are some fifteen or twenty, on either side."