The cove was still in deep silence, so finally Frank concluded that the men who had entered the place in the boat had retired to some secret hiding place. Inasmuch as they could not hope to discover anything without a light, he withdrew the flashlight from its case, and then switched it on.
The yellow beam of light revealed the pallid leaves of the bushes by the shore and the naked walls of rock above. But although Frank turned the flashlight in every direction about the cove there was no sign of the rowboat in which the two men had arrived.
It had vanished utterly.
Although the lads were prepared for the disappearance of the smugglers, they were not prepared for the disappearance of the rowboat. But they searched for it in vain. The light revealed nothing of the craft.
“I wonder where they hid it!” whispered Frank.
They began a systematic search of the bushes around the cove, remaining as quiet as possible, but although they made almost a tour of the place it was soon evident that the boat had not been beached under cover of any of the thickets.
“It must be hidden in a cave of some kind,” Frank decided at last. “And that’s where the smugglers are.”
Once again they began a search of the bushes.
They were still wading in the water and their feet were now very cold, but they searched patiently and carefully, brushing aside the branches, peering into the bushes, but it seemed they were to find nothing but the uncompromising rocks and moss beyond.
At last, however, as they were approaching a part of the cove which they had not visited before, Frank, who was in the lead, stumbled suddenly forward. His groping feet had failed to encounter bottom and he had lost his balance.
With great presence of mind, he kept the flashlight high in the air. He had stepped into a deep hole, and although he was up to his neck in water he kept his arm raised, keeping the flashlight free of the wetness.
“Here! Take the light,” he gasped, in a hoarse whisper.
Joe leaned over and grasped the flashlight.
“Deep water here,” muttered Frank, as he tried to scramble back into the shallows.
But the hole into which he had fallen was a sudden drop and it was necessary for Joe to grasp his brother’s outstretched hand before he could regain the shallow water. At length, soaked to the skin, Frank again stood beside his brother.
“Good thing it wasn’t any deeper,” he remarked.
“The bottom is pretty level around here. It’s funny there should be a deep hole like that.”
Frank gave a sudden exclamation.
“I know how that came to be there,” he whispered. “That’s a channel! See how close it is to the shore. The water shouldn’t be so deep right there.”
“Why should it be a channel?”
“To let that motorboat get into shore—or the rowboat. They’d run aground otherwise. Give me the light. I’ll bet we’ve found where that boat was hidden.”
He played the flashlight on the surface of the water and then they could see clearly that the bottom of the cove was broken by a deep channel at that point, several feet in width, leading directly toward a clump of bushes at the shore.
Keeping well to the side of the channel and in the shallow water, the Hardy boys made their way over to the bushes.
Then, when the beam of the flashlight was cast on the dense covert of branches, the mystery was clear.
Beyond the bushes was a dark opening in the rock.
“A cave!” exclaimed Frank, in a suppressed tone.
It was so cleverly concealed that it could not have been seen in the clear light of the day except at close quarters. The glare of the flashlight, however, cast the dark opening into prominence behind the screen of leaves.
This, then, was the explanation of the boat’s disappearance. There was a channel in the cove enabling the smugglers to row the boat directly into this cave in the rock. This also probably explained the presence of the motorboat.
“They went in here,” said Joe.
“We’ll explore it.”
Having gone so far, there was no going back. The boys were fully determined to keep on the track of the smugglers. They did not know what lay behind the darkness of that silent and mysterious opening in the rock. But they meant to find out, no matter what the risks.
Cautiously, they advanced into the bushes, which gave way protestingly before them. The branches whipped their faces. The water was still shallow, for there was a narrow ledge along the side of the channel and, moreover, it was now low tide.
At last the bushes closed behind them. The Hardy boys were standing in the entrance to a secret passage, pressed close against the rocky wall of the cave.
XVII
The Chamber in the Cliff
Frank switched on the flashlight.
The beam illuminated the depths of the dark passage. Far ahead of the brothers they glimpsed a grey shape just above the surface of the glistening water.
For a moment they were startled, then they recognized that the grey shape was nothing more than the rowboat that had passed by them in the darkness outside the cove. It had been drawn up close to a natural wharf hewn out of the solid rock. It swayed to and fro with the motion of the water.
The boys made their way forward along the ledge, which was wide enough for one person to walk on, until at last the ledge widened out and proved to be a path leading to the wharf.
There was not a sound in the passage but the drip-drip of water from the gloomy walls.
The Hardy boys stole quietly forward along the wharf, passed the boat, and then looked about them.
Frank played the beam of the flashlight all about the place until at last the glare revealed a
