Not one of that party drew a breath, as in the dying light the professor laid his hand on the upright pillar and pulled.
"Fooled again," burst out Ralph; but suddenly the professor, who had put his utmost strength into the task, went toppling backward, waving his arms like a scarecrow in a high gale. He fell on the marble floor with a crash, but was up again like a jack-in-the-box.
"Hooray! hooray! the old miner's writing was true!" burst out Ralph.
"Hush!" exclaimed Walt, "you'll have Ramon and his men in here in a moment."
As he spoke there came a sudden trampling of feet outside and shouts echoed.
"They've found us out!" gasped Ralph, with blanched cheeks.
"No, they're running past the door," exclaimed Walt. "Listen, something else is the matter."
"What can it be?" wondered Jack.
"No time for speculation now, my boy," warned the professor, who had recovered himself. "It's now or never. Are we going to chance the secret tunnel?"