“Slaves’ elbows, no doubt,” replied Frank, “the thousands of people who must have used this passage in the dead centuries could easily have worn away the walls in that manner. Just as,” he continued, “in old cathedrals you will find the altar steps worn by the knees of the countless worshipers who have knelt there.”
“Maybe they were bringing out treasure,” hazarded Billy.
“That’s entirely likely,” replied Frank, “in such a case their burdens would naturally have expanded their arms till they rubbed these grooves in the walls with the passage of time.”
The little party had come to a halt during this conversation, but now Frank turned to the others.
“We can take our choice,” he said, “of going on or of returning to the surface and getting together a more complete equipment.”
The unanimous vote was for keeping on, at least for a time, and the Chester Expedition under its young leader took up the march again. Now, however, the walls of the level passage along which they were proceeding seemed to have broadened out and they could walk three abreast without difficulty instead of proceeding Indian file as hitherto. The air of the passage too seemed purer than that of the staircase, and Frank even thought at times he could detect a cool draught, coming from some unknown outlet possibly. It was, however, insufferably hot; with the close, ardent heat of a coal mine.
The passage began to take a gentle gradient upward after they had proceeded along it for about half an hour, and as they pushed on the air grew noticeably fresher. When Harry held up his candle they could see that the roof of the passage was dripping with huge stalactites of a whity color that glistened as the flame fell on them. On either side too they could perceive the wet gleam of the walls. They were still in a confined place.
They pushed ahead in this manner for perhaps fifteen minutes more when suddenly Frank stopped short.
“Don’t come a step further,” he cried sharply.
The other boys poured out their questions.