A gradually rising wind began to rake the tree-tops and the swishing of leaves and creaking of limbs could be plainly heard. The dull booming of the waves on the distant shore, the moaning of the wind, the driving spatter of rain, the constant peals of thunder, continually rose in volume, and the rain poured furiously from the black skies above.
The storm had broken so suddenly that the Hardy boys were taken aback. Their first impulse was to race for the shelter of the cave, but second thought told them that this would be unwise, for the men in the cave might be aroused by the storm.
"We'd better go back to the boat," said Frank, turning about. "It's liable to be wrecked."
Joe had almost forgotten about their motorboat. It was on the seaward side of the island and the storm was coming in from the sea. Although the boat was partly protected by the little cove into which they had brought it, there was every danger that the storm might cast the craft up on the rocks and wreck it. The consequences, in that case, would be grave. They would be unable to escape from Blacksnake Island at all without giving themselves up to the gang.
The boys turned and fled back across the rocks. Rain streamed down upon them. Thunder crashed. Lightning flickered, illuminating for brief seconds the tossing trees and the tumbled rocks before them.
Joe, during the afternoon, had occupied himself ascertaining the position of the grove and the cave relative to the little bay in which they had left the motorboat and he had come to the conclusion that the grove was not far away from the end of the island and almost in a direct line with the cove. Now, in their mad race toward the shore, he took the lead, heading toward the rocky bluffs.
The Hardy boys stumbled through the grove, keeping somehow to the trail. They were aided by the lightning flashes that gave spasmodic illumination, revealing the soggy leaves, the black branches, the tossing tree-tops bowed in the wind.
The storm had become a din of furious sound. The gale shrieked its way across the island from the booming sea and the thunder rolled like a battery of cannon while the rain beat down on the forest in a drumming downpour.
The boys were soaked to the skin. They fled toward the shore, keeping their course more by instinct than judgment, and all the time there was the dread thought in their minds that they were lost if the Sleuth should be cast up on the rocks and wrecked.