By the aid of the tree limb the young diver crawled upward until he reached the trunk across the opening.
The branches were so thick he had to literally force his way along.
The opening was almost closed by the big tree trunk, but to one side there were several loose rocks, and after an effort he succeeded in shoving them into the hole and thus making a place through which he crawled, although not without great difficulty.
He was now free once more, and despite the fury of the elements set off for the camp with all speed.
To travel was not easy, and often he had to make a detour in order to avoid a fallen tree or a deep pool of water.
He was still a short distance from camp when there came another terrific whirl of wind that sent tree limbs flying in all directions. One struck Dave on the shoulder and hurled him flat.
"Phew! this is awful!" he muttered, and then stopped short, as a cry from a distance reached his ears.
"Help! help!" came in Doctor Barrell's voice. "Help, or I shall be killed!"