The airship was now less than half a mile distant, and from the altitude to which they had risen—some three hundred feet above the surface—the occupants could see every detail in the strange drama that was being enacted beneath them. Assisted by the figure above, the swimmer was gradually making his way on to the mast, when suddenly a black fin appeared above the surface a few yards off. With a convulsive movement, the lowermost man had just succeeded in swinging himself a foot or two up the mast when the gaping jaws of a shark passed immediately beneath him. Tom shuddered involuntarily. The man had escaped by a few inches at the most.
In a second the shark turned and glided beneath the clinging figure. The terror-stricken wretch clutched wildly at the man above him, and began to haul himself up hand over hand, clinging to his companion’s body. But the latter, unable to bear the double weight on the smooth mast, slipped slowly downwards. He was the slighter of the two, and no match, apparently, for the man who had usurped his place.
“What a beast!” ejaculated Tom, wondering at this strange want of fellow-feeling in a man who was evidently older and stronger than his companion in distress. Slowing down, he fixed his eyes on the extraordinary spectacle. The position was now reversed. The younger and slighter man was very manifestly the under dog. With every attempt on his part to swarm up the mast the man above him kicked savagely, while the shark circled below. The fact that the second mast had become untenable seemed to indicate that the tide was rising. Neither of the men, their whole attention fixed on the sea beneath, had noticed the airship that was now hovering just above their heads.
When, however, Tom gradually allowed the airship to sink towards the sea, the shark seemed to take fright, just as smaller fish are scared by signs of movement in the air above. It left the immediate neighbourhood of the mast, and its black fin could be seen describing a much larger circle some two or three hundred yards away. Clearly it had not given up hope. When the shark moved away and the strain of terror was relaxed, the two men became suddenly aware of the presence of the airship. The topmost man was almost as much scared by the sight of the airship as he had been by the presence of the shark. Tom had already noticed that both of the men were dark skinned. The larger and stronger—the brute, as Tom mentally called him—appeared to be middle-aged; the other was a stripling.
Tom was struck by the difference in their demeanour when they caught sight of the airship; neither he nor Timothy was at present visible to them. The elder man was aghast with fright, his eyes dilated, his mouth gaped between black moustache and beard. The younger, however, seemed to pull himself together as with renewed hope. Tom fancied that he heard a cry from his lips.
Looking round, Tom saw that the yacht had now hove to, and the boat was leaving her side. But his attention was again called to the wreck by a piercing shriek. The shark, regaining confidence, had made another dash at the mast. This time it seemed to come within an inch of the terrified youth; indeed, from the cry that had reached his ears, Tom thought that the poor wretch had actually been seized. But next moment he saw that the shark had again drawn off, scared, possibly, by the cry.
There was now less of the masts above the surface. The tide was evidently rising, and with its rise the shark would have another opportunity of coming within snapping distance. Tom felt that it would not again fail. It would be at least ten minutes before the boat reached the spot; by that time the hapless lad would probably have fallen a victim. Tom had noticed that when the shark was all but upon him, and he made a convulsive movement upwards, he was met by a storm of kicks from the man above, threatening to dislodge him completely from the mast and hurl him into the very jaws of the monster.
In a moment Tom made up his mind. He ordered Timothy to let down from the car a light grapnel carried for use in emergencies, and also for raising anything that might be needed, without having to bring the airship to rest on the ground. Then he allowed the machine to sink gently until the grapnel dangled within reach of the man at the top. Tom had no intention of helping him first; by his conduct he deserved to be left to drown or to make a meal for the shark. But the man seemed indeed quite incapable of movement, except when scared to frenzy by the efforts of the youth below to regain the position from which he had been forced. He made no attempt to clutch the grapnel dangling at his very hand. Tom let the machine fall lower, until the grapnel came within reach of the younger man. He showed no such hesitation. Looking along the cable, he saw Timothy gazing down at him from the car. The sight of a human face gave him confidence. He clutched at the grapnel, let go his hold of the mast, and swung clear, Timothy attempting to steady the rope.
His sudden movement threatened a catastrophe. The airship was now only about sixty feet above the sea, and before Tom, his attention partly engaged by the efforts of the boy, could increase the speed of the ascensional screw, the light vessel was pulled swiftly downwards. For a moment he felt that it must inevitably be dragged into the water. The young fellow below, still clutching desperately at the grapnel, had actually begun to sink beneath the surface. But as soon as his weight was supported by the water, the ascensional screw, now set by Tom whirling at full speed, checked the downward movement, and in another couple of seconds the airship began to rise, dragging the youth upwards.
In his excitement Tom had momentarily forgotten the shark. That persistent creature, however, having overcome its fear of the monster of the air, made a dash for the youth as he entered the sea. The poor wretch had the narrowest escape of all when the shark passed just beneath him, as, whirling round on the grapnel, he was swung clear of the water.