A ladder would solve the problem--but for numerous reasons it was a solution not to be thought of. Above all things, he wished his investigations to be absolutely unsuspected. If Darcy for an instant imagined that the truth was known, he would be off like a flash. If the Secretary was to conquer the secret of the tower, he must do it unaided, and he was about to turn back and descend, baffled by the hopelessly smooth surface of the structure, when his eye caught sight of a small iron ring in the side of the tower, about two feet above the roof of the house. Examining closely, he saw a second ring two feet above the first, and others at like distances up, presumably to the top, though the ivy had in some cases concealed them. His first conjecture was that at some time there might have been a rope ladder arranged; but that would have called for pairs of rings at the same level, and the closest scrutiny failed to reveal more than one. Perhaps, thought Stanley, it might be possible to rig some sort of a contrivance of rope to these, by means of which he might ascend; but it was difficult to procure the necessary material, and still more difficult to attach it to the tower without attracting observation. He caught hold of the ring and gave it a good jerk towards him to be sure it was firmly enough embedded to be of some service, when, to his utter astonishment, not the staple, but the block of stone to which it was attached, pulled out about six inches. Here was an unexpected _dénouement_. If the masonry was as rotten as all this, it was high time, for the safety of the house, that it was pulled down. A moment's examination, however, assured him that the tower was as solid as a rock. Why then should this one stone be loose, and why could he pull it no farther? He pushed it in again and pulled once more with all his strength, but it came only the six inches, and then remained immovable. He bent down and examined it closely. Then, as he perceived there was no trace of mortar on its edges, he gave a shout of exultation, and seizing the second ring, drew it towards him with a similar result. The stone to which it was attached pulled slightly out. Unwittingly, he had stumbled on to one secret of the tower. These stones formed nothing more or less than a concealed staircase; perilous indeed, but quite possible of ascent. Springing up on the first and second stones, he found they bore his weight, and he was thus enabled not only to steady himself by the rings above, but to pull them out in like manner. Having tested three or four and pulled out six, he descended again to the roof, and returned to his room to provide himself with certain necessaries for the trip, among which were a small bicycle lamp and a match-box. He took off his coat and waistcoat, and also his shoes, and set about making the attempt in a more practical manner. For at least half the way up he would be screened from view by the roofs, and for the remainder he must take his