With a trembling hand Zeta Phalos drew from his pocket the precious copy of the inscription. He and the professor bent over it, eagerly comparing point to point the indications on it, while the captain waited impatiently.
At last the two straightened up with delight in their eyes.
“No doubt about it!” exclaimed the professor. “It answers every requirement. Now to find a way in.”
A feverish search was made, and finally a crevice was discovered into which a man might worm himself behind the towering rock.
The captain turned about and shouted:
“Come along, Don! Come along, Teddy!”
He thought he heard them respond, although it was only an echo. Then, dropping on hands and knees, he worked his way through the opening.
The others, who were smaller and slenderer, followed the captain’s example, and all three were presently on the other side of the rock and in a narrow passage.
They straightened up and brushed off their clothes, expecting every instant to see the boys following them.
But no other form darkened the opening, and the captain grew impatient.