He put the tiller hard over in an effort to keep clear of the whirlpool, but its influence was extending. Already he could feel the drag of it, and the wind was too light to hold against it. The Sun Bird rocked, seemed for a second to hesitate and then gave up. Reluctantly she answered to the pull of the water and began to drift astern. A sudden terrifying roar broke out. Margaret's head appeared through the doorway.
'What-?' she began.
'Look out!' Mark shouted. 'I'm coming down.'
He slid swiftly down the side of the hull, swung himself through the opening and slammed the door behind him.
'What was it? It sounded like all the baths in creation running out at once.'
'Look there!' He pointed through the window, and together they peered out.
The Sun Bird was beginning to travel fast, close to the edge of the whirlpool. They could look right down into the hollow of spinning water.
'The bottom must have given way. Caves or something like that below.'
'Do you think-?'
'Can't say. There may be enough force to drag us down. Perhaps we'll just spin in the middle till it fills up.'
He drew her back from the window. She turned very wide eyes to stare into his.
'Oh, Mark, if-'
'Come on. We've got to strap ourselves into our seats. There'll be a hell of a mix-up in here if we do go down. Quick now.'
They both slid hastily into their seats and fumbled for the buckles of the broad webbing belts. The Sun Bird was circling the wall of water at a prodigious pace. She tore spirally down it to spin like a top at the centre. Mark hoped desperately. Would she ...? Would she...?
She canted. The water rose dark over the windows. She swung abruptly, nose down. There was sudden, complete darkness inside. A sense of weightless dropping. Down and down____
CHAPTER III
A watch would have told that the Sun Bird did not fall for many seconds—but seconds, infinitely drawn, mean nothing. She fell for an eternity. Uncannily like those dreams of Mark's childhood when he had slid faster and faster down a stair-rail which had neither beginning nor end. There was the same sense of plunging weightlessness; the same awful apprehension of the end.
But the end when it did come was, like so many ends, an anticlimax. There was a back pull as though brakes of unthinkable power had been applied to the full. The webbing safety belts were put to a strain which crushed the breath from their wearers' bodies. Mark could hear himself giving out involuntary, uncouth grunts. For a moment he feared that the belt might give and send him hurtling forward against the window, to smash or to be smashed. But the fabric held and the pressure swiftly eased. Presently he could draw a needed breath. Then abruptly the force reversed and they were thrust deep into their seats. 'Coming up again,' he told himself. The Sun Bird, carried to the depths by the fall, was rising bubble-like.
She broke the surface, spun like an ill-balanced top and was carried away broadside. He sat up and prepared to loosen the belt, but even as his fingers reached the buckle there came a thunder of water on the roof, loud despite the sound-proofing. The craft rolled like a floating barrel and sank again; rose again, and drifted back once more beneath the falls. She spun, twisted, rose and fell, like a wood chip beneath a weir. The brains of the two within swirled giddily.
'Nothing to do but hope,' Mark told himself. 'Bound to float free sooner or later____My God, to think that they pay for things like this at fun-fairs.... Hope I'm not going to be ill.'
At last came a bump and a slight grating along one side. They could feel a slow, deliberate swinging. Mark waited for a moment, then:
'We're out of it,' he cried, unbuckling the strap. 'Where's that light switch?'
The small ceiling bulb revealed Margaret's slight form still sunk in the seat. She made a feeble attempt to smile at him.
'But I do feel sick,' she said plaintively.
'I'll bet you do. Just wait a minute while I find that flask.'
Bast emerged from the safe hiding of some corner, and stood looking at them from bemused, greenish-yellow eyes. She gave an unhappy mew and advanced towards Margaret. How she had contrived to remain undamaged was an unsolvable feline mystery.
The brandy which Mark at length produced had an immediate effect, not only of settling, but of heartening. Margaret loosed her safety belt and stood up. She staggered slightly.
'The ill treatment, not the drink,' she explained. 'Where are we? It's all dark outside.'
'Heaven only knows,' Mark managed, with an effect of lightness. 'A cave I should think, but it's a mighty big one to take a fall like that.' He pushed over a switch. 'Damn, the headlight's not working. Now where the devil did I stow those spare bulbs?'
He was convinced in his own mind that the end was not far off. The water from above would plunge down until the cave was filled. The Sun Bird would rise until she met the roof and could rise no more. The water would close round her, trapping them helplessly. The air in the storage cylinders would last them a few hours, and then ...
'Ah, got 'em,' he said.
They were being rocked jerkily; swinging in a way which suggested that thev were caught in a current, but the darkness outside was too intense to give even a hint of their surroundings. He crossed the cabin and opened the back of the headlight set above the front windows.
'Now,' he said, snapping it shut again with the new bulb in place, 'we'll be able to see just what we've fallen into.'
A brilliant beam slashed into the blackness. About them was swiftly flowing water, bearing them along. A few yards to the left was a rock-wall passing with surprising swiftness. Mark switched the light ahead, but there was little to be seen save the water swirling beside the rock until it disappeared into obscurity. To the right also the water stretched out beyond the lamp's range. Far above thern the upsweeping curve of a rocky roof could be dimly seen.
Mark's spirits rose. At least, catastrophe seemed less imminent.
'Well, well, here we are. But where we are, and where we're going, the Lord alone knows,' he said.
He turned to look at the girl and his temporary spurt of lightness vanished. She caught sight of his expression and slipped her arm in his.
'Never mind, dear. It's not your fault. You couldn't know that the Sun Bird was going to misbehave like that, nor that this was going to happen. Besides we're both— well, we're in it together, aren't we?'
He looked down at her standing beside him. The white suit was sadly crumpled, a small, yellow bruise showed close to her right eye, the soft hair was a tangled, dark red disorder shot with gold lights, and the hazel eyes gazed steadily back at his own. He kissed her.
'You're lovely. And you're a brick,' he said.
A long time—or what seemed a long time—later, the right-hand wall of the cavern came dimly into view, converging rapidly to form a rocky tunnel ahead. Clearly this vast underground lake was narrowing to its exit. Mark focused the light forward, and viewed the prospect with no little misgiving. The speed of the water was perceptibly increased and the surface was broken by swirls and wavelets; it was impossible to tell how deep lay the rocks which must cause them. He wondered uneasily how long their luck would hold. One rocky spike could, at their present speed, rip the bottom from stem to stern. And to what were these rapids the prelude? Another fall would be likely to dash them to pieces. It had been mere luck that the earlier drop ended in a deep pool. Suppose a pile of rocks had lain beneath ...?