"What are you two boys trying to do?" inquired Ned approaching.
"Just getting some Fourth of July here, that's all," replied Jack.
"Try it again," Ned suggested. "Let me see, too."
"You do it just like this," directed Jack. "Harry had the end of the wire in that hole over there and I had the other end in this hole. Just as I pulled the wire out of this hole when we heard a noise, I saw fire flash and heard a little snapping or crackling sound!"
"Try it again," urged Ned. "Keep the wire in both holes!"
In a moment the boys had followed out Ned's instructions and all were startled to hear again the low rumbling, grinding noise.
"Keep your wires in place!" Ned whispered. "Something's coming off here that isn't on the program! Oh, look there! Look! Look!"
As he spoke Ned pointed to a section of the wall. It was slowly swinging outward from the room, revealing a doorway. A damp, musty odor came from the opening. Beyond all was pitch blackness.
The swinging section traveled easily backward until the doorway stood wide open. A snap was heard. For a moment the slight whirring noise continued, then the door slowly swung into place again.