"But we can't get into it."
"No, sir. But we can see it. I have an idea."
"I presume you have, Morgan," returned the ensign, smiling grimly. "And I have a glimmer of an idea myself."
When the men trooped in to breakfast the officer and Whistler Morgan stole away. The old woman was too busy just then to notice their absence.
In half an hour they found the place where the warrant officer and his companions had broken through the jungle. They retraced their course and soon came to the clearing in the wood.
It was a secret place, indeed. The cabin was ten feet square, built of heavy logs, and as Whistler had been told, had no window openings. The door of heavy planks was fastened by a huge hasp held in place by the padlock mentioned so particularly by Ikey Rosenmeyer.
"I guess we can't get into it without tools," said the ensign.
"I don't suppose so, sir. But see that pole on top of the cabin? That had the upperworks of a wireless attached to it, I'm sure. The bolts are still up there. It is no flagpole."
"Right again, Morgan," agreed Mr. MacMasters.
"And that piece of a letter to Linder," the boy eagerly reminded him. "Don't you think with me, sir, that the old woman is linked up with the German spy system?"