I now learned for the first time the cause of my ten ships' retreat from the mouth of the shaft. It seemed that when they had come upon the shaft the navy of the First Born were already issuing from its mouth. Fully twenty vessels had emerged, and though they gave battle immediately in an effort to stem the tide that rolled from the black pit, the odds against them were too great and they were forced to flee.
With great caution we approached the shaft, under cover of darkness. At a distance of several miles I caused the fleet to be halted, and from there Carthoris went ahead alone upon a one-man flier to reconnoitre. In perhaps half an hour he returned to report that there was no sign of a patrol boat or of the enemy in any form, and so we moved swiftly and noiselessly forward once more toward Omean.
At the mouth of the shaft we stopped again for a moment for all the vessels to reach their previously appointed stations, then with the flagship I dropped quickly into the black depths, while one by one the other vessels followed me in quick succession.
We had decided to stake all on the chance that we would be able to reach the temple by the subterranean way and so we left no guard of vessels at the shaft's mouth. Nor would it have profited us any to have done so, for we did not have sufficient force all told to have withstood the vast navy of the First Born had they returned to engage us.
For the safety of our entrance upon Omean we depended largely upon the very boldness of it, believing that it would be some little time before the First Born on guard there would realize that it was an enemy and not their own returning fleet that was entering the vault of the buried sea.
And such proved to be the case. In fact, four hundred of my fleet of five hundred rested safely upon the bosom of Omean before the first shot was fired. The battle was short and hot, but there could have been but one outcome, for the First Born in the carelessness of fancied security had left but a handful of ancient and obsolete hulks to guard their mighty harbour.
It was at Carthoris' suggestion that we landed our prisoners under guard upon a couple of the larger islands, and then towed the ships of the First Born to the shaft, where we managed to wedge a number of them securely in the interior of the great well. Then we turned on the buoyance rays in the balance of them and let them rise by themselves to further block the passage to Omean as they came into contact with the vessels already lodged there.
We now felt that it would be some time at least before the returning First Born could reach the surface of Omean, and that we would have ample opportunity to make for the subterranean passages which lead to Issus. One of the first steps I took was to hasten personally with a good-sized force to the island of the submarine, which I took without resistance on the part of the small guard there.
I found the submarine in its pool, and at once placed a strong guard upon it and the island, where I remained to wait the coming of Carthoris and the others.
Among the prisoners was Yersted, commander of the submarine. He recognized me from the three trips that I had taken with him during my captivity among the First Born.