And so it was arranged. Percy promised that he would be on hand at an early hour; and he suggested that not a word should be spoken on the subject to others. “Only to Mary,” said our heroine, earnestly. “I will be responsible for her circumspection.” “Certainly,” returned Percy. “You shall not go without your trusty attendant. But you will caution her in advance.” The girl promised that she would exercise all possible caution, and shortly thereafter the young man took his leave. The morning of the following day dawned clear and bright, and by the time the sun was two hours high the party was ready for the excursion to the old chapel. By previous arrangement Percy had brought his old fowling-piece with him; and the earl likewise took one, thus giving to the inquiring servants the impression that they were going out simply for shooting. Cordelia often accompanied her old guardian on his woodland rambles, gun or no gun; and more than once Percy Maitland had been called to go with them; so the arrangement of the party caused no surprise. On referring to his watch, when they had reached their destination, the guide found it to be only a few minutes past eight o’clock. They were in good season, and he felt very confident that they had nothing to fear from other parties in the cavern. Cordelia was in a flutter of excitement as they approached the altar. Percy first pointed out to them the peculiarities of the huge stone. He found his wooden probe which he had fashioned on the previous day, and with the aid of that he very soon explained the various points, the discovery of which had led him to the grand discovery of all. This done, he went to the right-hand end of the block, and laid his two strong hands fairly on its upper edge. “Now, my lady,” he said, with a happy smile, “if you will keep your eyes open you will behold a wonderful thing.” A weaker man than he could have set the rock in motion. He put forth his strength gradually, for the purpose of testing the matter, and he had exerted not more than a moiety of it when he felt the ponderous mass give, and heard the sharp click of the spring beneath. A moment later the end of the stone where they stood began to move--to swing outward, away from the wall--and in a few seconds the aperture underneath was exposed to view. Never mind the loud astonishment of the lady, nor the more quiet surprise of the maid. The earl himself was filled with wonderment, and did not hesitate to acknowledge it. The whole thing was a wonder, not only the finding of the subterranean chamber and the marvelous mechanism by which the altar was controlled, but the very existence of the place.