“I’ll go, if you will,” replied Laurie, stoutly; and without much enthusiasm Bob ducked his head and crawled through. Past the two-foot wall was a passage, more than head-high and about a yard in width, stone walled and arched, that led straight ahead farther than the light of the lantern penetrated. The walls were dry, but the earthen floor was damp to the touch. There was a musty odor, though the air in there seemed fresh.
“Where do you suppose it goes to?” asked Bob, in a hushed voice.
“I can’t imagine. But it runs straight back from the cellar, and so it must pass under the garden. Let’s—let’s go on, Bob.”
“Sure! Only I thought we were going to find old Coventry’s treasure!”
“How do you know we aren’t?” asked Laurie.
“That’s so! Maybe he buried it under the garden.” Their footfalls sounded clearly on the hard-packed earth floor as they went ahead. Suddenly Bob, in the lead, uttered an exclamation, and Laurie jumped a foot and then hurried forward to where the other was standing. Beside him, its point buried in the floor of the tunnel, was the lost crowbar!
“What do you know?” gasped Bob. “We’re under the farther end of the arbor. That bar came through between those stones up here.” He touch the crevice in the arched roof with a finger. “See the dirt it brought down with it? Well, that explains that mystery!”
“Yes, but—where does this thing go to, Bob?”
“Let’s find out. It can’t go much farther, because the arbor was only about forty feet from the back fence.”
But they went that forty feet and perhaps forty more before the wavering light of the lantern showed them a stout wooden door across their path. Formed of two-inch planking and strengthened with three broad cleats, it was hinged to a frame of concrete. It wasn’t a big door, but it looked very formidable to the two boys who stood there and viewed it dubiously in the yellow glare of the lantern; for a big square iron lock held it firmly in place.