It was merely a faint depression in the deep grass, but it proved that more than one person had passed that way before. The trail wound along through the verdure, away from the shore, leading toward the interior of the island.
“Well, if someone else has gone this way, we can follow the path, too,” Joe remarked. “Got your gun?”
“Yes.” Frank patted his hip. Both boys had provided themselves with revolvers before leaving home. They were not adept with firearms, but the nature of their mission had prompted them to come prepared for any emergency. Fenton Hardy had a collection of weapons in his study, all trophies of his various cases, and the Hardy boys had each taken a small and efficient-looking automatic pistol for protection.
They struck out along the faint trail, the grass rustling about their feet. The green thicket loomed ominously before them and the heat became more intense.
Frank was striding along in advance, gazing at the thicket ahead, when he suddenly came aware of a disturbance in the grass almost at his feet. Some sixth sense warned him of danger. That strange tickling of the spine, man’s instinctive reaction to the presence of a hidden peril, made him look down.
Immediately in front of him lay a huge blacksnake!
The reptile was easily five feet in length, and as the boy leaped back he could hear a prolonged hissing. The snake writhed and twisted, and its head came into view from amid the grass, the red tongue flickering wickedly.
Frank saw that the snake was coming directly at him. He leaped to one side, at the same time snatching his automatic from his hip pocket. He had not time to aim, but he pressed the trigger and pumped two shots in the direction of the reptile.
The snake stopped dead, then swiftly began to coil itself up in readiness to strike.
Not a word had been spoken. Frank had blundered back against Joe, who was unaware of the cause of his brother’s sudden alarm. He quickly grasped the situation, however, and looked about him.
Close at hand, almost hidden by the grass, was a heavy stick. He bent and quickly snatched it up.
“Quick!” said Frank, taking it from him.
He brandished the stick and brought it down with terrific force upon the snake. The first blow did not kill the reptile, although it rendered it helpless. The hissing continued, the scarlet tongue flickered like flame. Then the boy brought the stick down again. It crushed in the evil black head. A few spasmodic wriggles, and the snake lay still.
“Whew!” breathed Frank, stepping back. “What a big brute he is!”
The boys inspected the reptile more closely, repressing a shiver of repulsion as they saw the sinuous, scaly body lying there in the grass.
“We’d better get away from here. Path or no path. Where there’s one snake there are more. Its mate is probably close by.”
The boys retreated until they gained the comparative safety of the rocks.
“It’s lucky for me you saw that stick,” declared Frank. “He was coming right for me, and the automatic wasn’t much use. He was moving so quickly I couldn’t have shot him. He was stirred up and angry, too. I guess I must have disturbed his morning nap.”
“We’ll stick to the rocks for a while, I guess. It’s time enough to go nosing around the interior when we’ve finished with the outside of the island.”
The boys descended a rocky slope that led into a small bay protected from the sea by a black reef. There were no snakes in sight as they skirted the shore, and then they came upon a well-beaten path leading up the side of a cliff.
“By the look of this path, the island isn’t as deserted as it looks,” Frank commented. “Perhaps we’ll have better luck following it.”
The path wound about among the rocks, seemingly in an aimless fashion, now diverging toward the shore, now bringing them farther inland. They followed it doggedly, however, convinced that it must have an ending somewhere, and that the termination would give them some clue as to the people who had used the trail before.
The trail at length brought them in front of a huge black opening in the rocks. It was a cave, over twelve feet in height, dark, gloomy and forbidding.
“Now what?” asked Joe.
Frank glanced at his brother.
“Shall we go in?”
“You can’t scare me. If you’ll go, I’ll go.”
“The trail leads here. Other people must have gone in here. If they can do it, so can we.”
“Lead on!”
Frank picked up a heavy stick lying among the rocks near the entrance to the cave. “You never know when we’ll run into snakes around here,” he remarked. “It’s just as well to be ready for them.”
Joe hunted around until he, too, found a club that would be serviceable in the event of their encountering more of the reptiles. He patted his hip to make sure that the automatic was still in his pocket.
“All set?”
“All set.”
Frank stepped forward and entered the mouth of the cave. Joe followed at his heels.
For several yards the cave was illuminated by the light from outside, but as they went on the gloom became deeper until at length they were faced by impenetrable darkness. Frank had brought with him a pocket flashlight and he switched it on. A wide ring of light shone before them, showing the damp rock walls ahead.
They stepped forward cautiously. The floor of the cave sloped upward, but the great opening in the rock was of such extent that the ceiling was scarcely visible above in the light of the flash.
“I don’t know where we’re going, but we’re on our way,” said Frank, as they toiled on up over the rough rocks. His voice awakened tumultuous echoes that were flung back and forth from the massive walls.
The flashlight showed him at length a place where the floor dipped abruptly to a steep slope, although there was still a wide ledge at
