"Ask Captain Hallowell to come here immediately," he said, and severed the connection.
He seemed already to have decided upon some sort of a plan, and his decisive manner gave the two lads a feeling of confidence in him. He reached into a drawer of his desk and drew out a large map. He ran his fingers across it and then came to a stop at a little black dot which appeared just in the angle of two converging red lines.
"Is that it?" he asked, turning to Jerry and Frank.
They examined the map carefully for a moment and then told him that it was.
Just then Captain Hallowell entered. His boots were spattered with mud, his face was grimy, and his eyes were bloodshot, indicating that he had been for many hours without sleep.
"Captain," said the colonel bluntly, "these young men are of the Signal Corps, as you you can see. They were detailed to-night to establish an outpost wire communication to Hill No. 8. You know it?"
"Very well, sir," the captain replied, his interest increasing.
"Well," continued the colonel, "they got there all right. But the other three in the party had hardly entered that hole when the entrance caved in."
"Great Scott!" ejaculated the captain. "I know that cavern. They can't last there long."
"Exactly," affirmed the colonel. "What is your suggestion?"