“Yes, and what are they handling?”

“Why, ore, of course.”

“And do you see nothing significant in that?”

“To be sure!” I exclaimed. “Why, that ore—”

“Hush! hush!” admonished Hall, putting his hand over my mouth; “don’t talk so loud. Now go on, in a whisper.”

“The ore,” I resumed, “may have come back from the furnace-room, because the side tunnel turns off so as to run parallel with the other.”

“It not only may have come back, it actually has come back,” said Hall.

“How can you be sure?”

“Because I have been over the track, and know that it leads to a secret apartment directly under the furnace in which Dr. Syx pretends to melt the ore!”

For a minute after hearing this avowal I was speechless.