It was a new sensation, this walking along the bed of the ocean. At first the great pressure of water, even though the steel lined diving suits kept most of it off, was unpleasant. Gradually, however, the boys became used to it. They had to move slowly, for the water was denser than the air and impeded their progress.
In a few minutes they reached the forward end of the Porpoise. Now they were to solve the mystery of what had stopped the submarine. For a few moments they could distinguish nothing.
Suddenly the boys felt the professor grasping their arms. They looked in the direction he pointed. There in the diffused glare from the search light and the illumination of their helmet lamps they saw, wrapped about the forward shaft opening a gigantic squid or devil fish. Its soft, jelly-like body completely covered the opening of the shaft preventing any water from entering, and thus stopping any forward motion to the ship.
This was what had caused all the trouble. The Porpoise had run into the monster, who feeling what it must have thought an enemy, had grasped the submarine with its long sinuous arms.
The professor hesitated a moment. Then he slowly raised his electrical gun, and took aim at the hideous mass. The boys followed his example. At Mr. Henderson's signal they all fired together.
From the muzzles of the guns darted small barbs that carried with them a strong shock of electricity, from storage batteries in the shoulder pieces of the weapons. Three of them were enough to produce death in an animal as large as a whale.
The devil fish quivered. Then the water about it suddenly grew black, and the boys and the professor were in dense darkness, for the squid had dyed the ocean with a dark liquid from the sack it carried for the purpose.
The explorers groped their way to the left, having fortunately grasped hands after firing their guns, to prevent being separated in case the terrible fish began a death struggle.
Luckily Professor Henderson went in the right direction and managed to locate the Porpoise. Then, feeling along her steel sides, he led the boys through the inky blackness to the water chamber by which entrance could be had to the interior.
In a few minutes all three were safely inside and had removed their diving suits. The others crowded about, anxious to learn what had happened. The inventor related it briefly.