They examined the various bars to the windows and began operations on one which looked to be more loose than the others. But though they worked with a will on the mortar with their pocket-knives, the stuff was hard and defied all their efforts. “We ought to have one of Hockley’s dime novel heroes here,” said Sam, grimly. “He’d twist this bar out in a jiffy.” “Or one of the half-dime novel detectives,” returned Darry. “He’d find a secret passageway leading down into a counterfeiter’s den, with a trunk full of gold in the bargain.” “Well, this is no laughing matter, Darry. That ride made me hungry. If I had known this I’d had breakfast before I started.” “Yes, indeed, and I’d have packed a big lunch box in the bargain, Beans. But don’t mention food--it only makes me more hungry. Let’s take another look around.” “Bound to find that passageway to the counterfeiter’s den, eh? All right, Old Flashlight, go ahead and make yourself famous.” Both boys laughed in spite of the seriousness of the situation, and then began another hunt around the room. “I see something that I didn’t notice before,” observed Darry, after searching around for quarter of an hour. “Do you see this wall? Right above my reach it is depressed for about a foot. If you’ll boost me up to the ledge I’ll feel around there for an opening.” “To be sure I’ll boost you up. But don’t fall and hurt yourself.” Once up on the ledge, Darry felt around with care. As before, he found plenty of dirt and mixed in with this were two or three musty books, a couple of empty bottles, and other odds and ends of no value whatever. “Here’s some reading for you--it will help to pass the idle hours,” cried Darry, tossing the books to Sam. “They are Spanish prayer books,” said Sam, examining them by the light of one of the windows. “They are dated fifty and sixty years back.” “I thought I had struck rare volumes worth a few thousand dollars,” returned Darry, dryly. “Too bad! Old Flashlight must renew his wondrous search! If we only--hullo!” Darry broke off short and Sam heard the creaking of rusty iron. “What have you discovered now?” he asked, after an anxious pause. “Discovered a door, as sure as you live!” exclaimed Darry, and now he was quite excited. “Hurrah, it’s daylight!” He had pushed in a small iron door and true enough both could see a streak of sunlight beyond, streaming into a small stone passageway. In the passageway was an iron ladder, leading to the flat roof of the building. There was a trap door above, which the storms of years had moved several inches out of place. It did not take Darry long to give Sam a hand up to the ledge, and then both boys entered the little passageway and crawled up the iron ladder. The trap door was thrown open and they came up onto the flat roof of the building. Near at hand was a sloping roof and also a square tower, all much dilapidated and covered in spots with heavy trailing vines.