Passing out of the royal bed-chamber, the boys hastened again into the main passageway, going further north than they had yet been in their flittings through the concealed walks.
Henri finally stopped over a big brass plate set in the floor.
“It is not like moving that slab last night,” he commented, as the plate dropped with a snap on easy hinges by some combination which Henri well knew how to work.
A spiral staircase was revealed, and round and round and ever downward the boys proceeded.
At the foot of the staircase, at the end of a short passage, the trio were confronted by what was apparently a blank wall.
Henri counted to himself as he passed his hands over the face of the wall. When satisfied that his calculations were correct he called to Billy to give him a lift. Billy promptly furnished a pair of square shoulders, upon which Henri stood, after removing his shoes.
Henri tapped smartly at a selected spot, a hidden spring was released and a section of the wall fell away.
Once astride of the cross-piece upon which the moving section had rested, Henri lent Billy a helping hand, and Billy in turn gave Reddy, the lightweight, a stocky leg on which to climb.
The boys then dropped down on the other side.
They were in the treasure house of the Trouvilles!