“I see,” Nick remarked. “I think I will go down there, Frank, and look around a bit. Show me the way as far as the stairs, then leave me, and pay no attention to my doings. I may have something to report a little later.” Frank Mantell arose to obey, and Nick accompanied him down to the ground floor. As they were turning toward the stairway leading down to the basement receiving room, Frank touched the detective’s arm and said quietly: “There goes Lombard, now. I think he is going down to the receiving room.” Lombard was heading for the stairs with a wrapped bundle about a foot long and nearly as large in diameter, but he did not see Mantell and his companion. Nick watched him for a moment, then said quietly: “Leave me, Mantell. I can find the way by following him.” Nick had more than one object in doing so. He arrived at the head of the stairs just as Lombard turned to the left in the great basement room. Nick darted down after him, and again fortune favored him. He reached the entrance to the room, which was always partly filled with unopened packages of divers descriptions, just in time to see Lombard glide stealthily back of a high pile of cases about two feet from one of the walls. Nick saw an empty case about ten feet to the right of the door. He crouched behind it and waited. Less than two minutes had passed when Lombard returned--without the bundle. He quickly reached the stairway and hurried up to the business part of the store. Nick Carter’s eyes had a sharper gleam when he crept from his concealment. He at once gave his attention to the narrow passage in which Lombard must have left the bundle. One side was formed by the high pile of cases. On the other was a sheathed wall. Nick examined the cases in rapid succession, and he soon found that none of them could be opened. Obviously, none could be a hiding place for the bundle. Nick then began a careful inspection of the wall, sounding it foot by foot by tapping it with his knuckles. He suspected, of course, that there might be a secret panel with an open space behind it. Presently he found a spot that sounded more hollow than other sections. “By Jove, I think I’m right,” he muttered. “But there seems to be no crack or crevice. The panel, if there is one, is most cleverly concealed.” Persistently searching the wall, however, Nick finally discovered the head of a nail some six feet above the floor. It did not appear to be as dusty as the rest of the wall. He reached up and pressed it with his thumb. This instantly brought a faint click from behind the sheathing. A section of it about two feet square, so neatly fitted that the cracks were invisible, separated from the rest and swung outward under the impulse of a hidden spring. It brought to light the foundation wall of the building, also a circular metal plate about fourteen inches in diameter, with a handle by which it could be swung downward parallel with the face of the wall.