"Good stuff!" cried Merry, approvingly, as he grasped the hand of his comrade. "We"ll both stay till we find her."
In a short time the boys began to feel like themselves once more.
Taking their wheels along, they sought for a spring, and were able to find one.
There they stopped and made a meal from the hard bread and jerked beef, which was washed down with clear water from the spring.
"Now I am all right," Harry declared. "A feed was what I needed."
They discussed matters a few minutes, and then, carefully observing the surroundings, decided to conceal the bicycles in the vicinity of the spring and seek for the mouth of the cave once more.
They found a good hiding place for the wheels, and there the machines were stowed away.
"We can"t be so awfully far from that cave," Frank decided. "One man and a girl would not be able to bring us a long distance."
But the cave was not easy to find, and the more they searched the more bewildered they became.
Meanwhile night was coming on swiftly.
"Hist!" warned Harry, suddenly grasping Frank"s wrist and drawing him down behind some bowlders. "Look there!"
"What is it?"
"Moving figures! I saw them distinctly over there."
"The man and the girl?"
"Couldn"t tell. There they are again. Look!"
"I see! It is not the man and the girl. It is two men."
"That is right--or, at least, a man and something that resembles a man."
"It is Bernard Belmont and his gorilla man!"
"You are right, Merry, my boy; and they, too, are searching for the mouth of the cave. It will be a good scheme to watch them."
CHAPTER XVI.
LOST UNDERGROUND.
The boys followed Belmont and Apollo, being aided in doing so without danger of discovery by the gathering darkness; but they knew very well that, in a short time it would become so dark that they might lose track of the two.
Apollo seemed to be guiding his master to some spot, and they clambered over the rocks with haste that indicated a desire to reach the place without delay.
At last the dwarf paused and swept aside some matted vines from the face of what seemed to be a cliff of solid stone.
A black opening, large enough to admit a man in a stooping posture, was revealed.
Apollo urged Belmont to follow, and then they disappeared beyond the vines, which fell down and hid the opening again.
"It"s a cave, Merry!" whispered Rattleton.
"Yes," nodded Frank; "it may be one of the many entrances to the great cavern of the "queer" makers. This may lead into the cave occupied by Carter Morris!"
"Then let"s get in there quick!" exclaimed Harry, eagerly. "If we don"t, we may lose track of those men."
"We must use something like caution, my boy. If we were to rush in after them, it might do us up, for they may be laying for us."
So the mouth of the cave was approached with caution.
When they had reached it, Frank listened.
From a distance inside he could hear voices, and, peering through the vines, he caught the glimmer of a light.
"Come in quickly after me, Harry," he directed. "Be ready to fight for your life if attacked."
Rattleton"s heart was in his throat, and he felt that they were plunging into unknown and terrible danger, but he said:
"Go ahead. I am with you to the end."
Gently and swiftly Frank made the opening in the vines larger, and then he quickly stepped through, holding them aside for his friend to follow.
The vines fell back into place, and the lad crouched close to the ground.
"There," said Frank, "see that light? It is not a torch."
"No. It seems to be some sort of lamp."
"It is a miner"s lamp. Look--another is being lighted."
A match flared up, and its bright glow revealed the pale and terrible face of the gorilla man, who was lighting the lamp.
The lamps were arranged to be placed in the hats of those who carried them, and this was what the two men did with them.
When everything was arranged to their satisfaction, Belmont and the dwarf started onward into the cave.
"We"ll follow them, Harry," said Frank.
The light from the lamps made it a comparatively easy task for the boys to accomplish their purpose.
Deeper and deeper into the great cave went the two men. Once or twice they stopped and listened. Once the boys distinctly heard Apollo say:
"Master, I think I heard a step."