"If we are determined to know it, Mr. Ward, the solution is only a solution of expense. Pickaxes and dynamite would soon conquer those walls."

"No doubt," responded the chief, "but such an undertaking hardly seems justified, since the mountain is now quiet. We will wait awhile and perhaps nature herself will disclose her mystery."

"Mr. Ward, believe me that I regret deeply that I have been unable to solve the problem you entrusted to me," I said.

"Nonsense! Do not upset yourself, Strock. Take your defeat philosophically. We cannot always be successful, even in the police. How many criminals escape us! I believe we should never capture one of them, if they were a little more intelligent and less imprudent, and if they did not compromise themselves so stupidly. Nothing, it seems to me, would be easier than to plan a crime, a theft or an assassination, and to execute it without arousing any suspicions, or leaving any traces to be followed. You understand, Strock, I do not want to give our criminals lessons; I much prefer to have them remain as they are. Nevertheless there are many whom the police will never be able to track down."