‘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 …?
The same thought was in Margaret’s mind as she gazed frowningly forward; nevertheless, she managed to put some lightness into her tone as she spoke:
‘I hope to goodness it’s not another fall – I’m still feeling a bit sick from the last. I always thought that the people who go over Niagara in barrels were fools; now I know it.’
Mark drew her back from the windows.
‘Better be on the safe side,’ he said, pointing towards the seats.
The walls of the cavern closed in to leave a channel sixty or seventy feet wide. The Sun Bird was swept helplessly towards it, swinging and bobbing like a cork. Both held their breath as the course narrowed. It seemed impossible that they could safely clear the jutting spur at the left of the entrance. The stream gripped them, thrusting forward as if it could know no greater joy than to crush this metal eggshell upon sharp, savage rocks. Then, at the last moment, an outswirl of current deflected them. They were rushed past the spur with only a few inches to spare.
The searchlight had been left switched on, but it served only to heighten the effect of confusion. The beam flung erratically from side to side, confounding all sense of direction and giving every moment the impression that they were about to crash against one side or the other. Half a dozen times ominous scrapes on bottom or sides set their hearts pounding. One jolt after another convinced Mark that they were holed at last, but after each he was able to look round the cabin and see with relief that there was still no sign of leakage. It was a sharp cry from Margaret which managed, after twenty or more apprehensive minutes, to direct his attention farther ahead.
‘Look!’ she cried. ‘Light!’
He stared through the forward windows. The motion made it difficult to be certain, but he seemed to catch a glimpse of a small patch of grey.
‘Reflection,’ he suggested.
‘No, it’s quite different. A colder, bluer kind of light than ours.’
He looked again, more carefully. The luminosity showed now in the shape of a high, almost Gothic, arch. ‘As though,’ he told himself, ‘the end of this tunnel were silhouetted.’ And its colour was, as Margaret had said, blue compared with the searchlight. Phosphorescence? But why should there be sudden phosphorescence? There was no trace of it in the water about them; a puzzle indeed, but soon to be solved, for their pace showed no sign of slackening.
He had to watch the opening grow larger and nearer for a longer time than he had expected. Distance in this darkness was deceptive, and his desire to be clear of the immediate dangers of the tunnel seemed to increase it. By the time they swished out upon a second lake, he felt that miles had been covered. They left their seats when the former jerky progress subsided into a smooth gliding, and stood close against the windows. The silence of astonishment was broken by Margaret.
‘It’s impossible! I don’t believe it.’
Mark, too, felt that the scene was more like a dream than a reality.
They were gazing across a lake which filled one of the largest caverns he had ever seen. So large was it that he looked apprehensively above; it seemed incredible that such a span of rock could be sustained without the help of pillars. But the size of the place, the acres of subterranean water, accounted for only a small part of their astonishment. The phenomenon at which they stared openmouthed was a system of lighting, beyond any doubt artificial.
At regular intervals about the roof were set globes which had the appearance of being frosted glass. From each came a glow of soft intensity, a light which was blue-white, yet not dazzling.
Mark’s earlier anxiety was supplanted by a fresh nervousness. The lights had been erected for some purpose. But what purpose? And by whom? Hitherto they had faced natural, and roughly calculable dangers. All had depended on the Sun Bird’s ability to survive; with her they had stood to live or perish. But with the discovery of the lights, a new element entered. They had been carried up against the unknown and, as always when all preconceived likelihoods are flouted, trepidation came crawling in. Men, he told himself, had put those lamps there – that could not be doubted. But what kind of men? What were men doing in these deep-sunk caverns? Moreover, these glowing globes were unlike anything he had ever seen before – there was an entirely unfamiliar quality in the light they shed. As far as he could tell, they were a discovery not known above. What sort of reception might await intruders upon men who had for some reason hidden themselves deep and unsuspected in the earth? He glanced at Margaret, troubled. She was no longer gazing at the lamps; her attention had turned to the walls.
‘Look, Mark,’ she said, ‘caves, there, above the waterline.’
He followed her pointing finger to see several openings, some near the water, others high in the wall, close to the roof. Moreover, he caught a detail which had escaped her. From the mouth of the largest a line of shadow ran slanting down into the water. A casual glance suggested a crack in the rock face; a longer look abolished the notion that it could be accidental.
‘It’s a ramp,’ he said. ‘A path leading up to that cave …’
For a few seconds he hesitated. They were drifting slowly now, and their course would take them not far from the wall. A disinclination to leave the comparative safety of the Sun Bird fought with the idea of a possible way back to the surface. To stay on board meant that they would allow themselves to drift farther and deeper into this maze of caverns. Already an unknown number of hundreds of feet lay between them and the daylight, and there was no guarantee that the exit from this lake would not take them over another fall. On the other hand, who – or what – might they encounter in the caves?
It was a choice of unknowns, but with the balance slightly in favour of exploration. After all, they could moor the Sun Bird, and have her ready for retreat. If they were to go on, there might be no other chance of landing. He pulled off his coat, and sat down to loosen his shoes, giving instructions to Margaret as he tugged at the laces.
‘I’m going to swim over to that ramp. I want you to get on top and throw me a line when you’re near enough. The control wires we used for mooring should be long enough if you join them. Think you can manage?’
She nodded, and started to search for the wires. Mark opened the door and dived out without hesitation; within ten minutes the manoeuvre had been accomplished. Mark had caught the curling wire, and the Sun Bird’s metal belly was grating noisily as he pulled her bows on to the ramp. Margaret sprang down and stood beside him, watching him make fast.
‘Isn’t it quiet?’ she said unhappily. ‘I didn’t think anywhere could be so horribly silent.’
Though she spoke in a low voice, the echoes managed to catch it and fling it eerily back and forth until it was no longer her voice, but a wandering, elemental sound. She shivered a little.
‘I don’t know which is worse, the silence, or the echoes.’
They listened for a moment to nothing. The silence sang in their ears with only an occasional clop-clopping of ripples to break it.
‘Well,’ said Mark cheerfully, ‘as long as there’s nothing but silence we needn’t be afraid.’
The travesty which the jeering, booming echoes made of his statement seriously dismayed both of them. They glanced nervously at one another. Margaret took his arm.
‘Do you really think we can get out that way?’ she asked, looking up the ramp.
‘Of course,’ he managed with more conviction than he felt. ‘The air’s fresh here. There must be some way for it to circulate. If we can only –’
The rest of his sentence was drowned. There came the rumbling of a mighty crash, thunderous in the closed space. The solid rock beneath their feet trembled. Mighty reverberations like great breakers of sound buffeted back and forth across the cavern lake. A hundred yards along the wall a poised mass of rock detached itself and fell deafeningly into the water. Margaret’s grip tightened on his arm. He could see her mouth forming inaudible words.
‘Look!’ he shouted, pointing back at the tunnel through which they had come.
A sudden wave of frothing water came charging out to spend itself upon the broader surface of the lake.
‘The roof must have dropped in. We were just in time: there’s no going back that way.’
Margaret’s alarm abated as the echoes became more feeble. She made an attempt to meet the latest calamity with lightness.
‘Never mind, my dear. There never was. Only salmon can climb waterfalls.’
4
‘Now, have we got everything?’ Mark said thoughtfully.
He looked in a calculating manner at the bundle beside him, and began to tick off the items on his fingers.
‘Food, bottles of water, flashlights, string, matches, knife … Lord, I nearly forgot …’
He slid from his seat and went to rummage in a locker. Margaret sat where she was, watching him extract a small pistol and drop it, along with a number of cartridge clips, into his pocket.
‘Why?’ she asked.
He shrugged his shoulders. ‘I don’t suppose we’ll want it, but – well, it’s better to have a pistol you don’t want than to want a pistol you’ve not got. We may run across – er – savage tribes or something when we get out.’
Margaret shook her head. The last sentence had been particularly unconvincing.
‘Mark, you’re trying to hide something from me. What are you afraid of?’
‘Nonsense. I’m not afraid of anything. What is there to be afraid of? I’m just being prepared, that’s all – old boy scout motto.’
‘Mark, don’t be a fool. I don’t in the least mind being protected, but I will not be treated as an idiot. What is it?’
He looked at her for a moment.
‘Sorry,’ he apologized. ‘You’re right, I was being a fool. I won’t play at he-men any more. Quite frankly I don’t know what to expect. It’s all so queer. First the lights, obviously put here for a purpose – but for what purpose? And then this ramp which may have been partly natural, but has certainly been finished off by hand – and not in a day or two, either. Whoever did it has kept it a good secret from the people above. It’s ten to one that they – er – well, that they probably want to keep it a secret.’
‘They may kill us, you mean?’
‘I can’t possibly say – that’s why I’m being prepared.’
‘But, Mark, who can they be? Surely there would be some rumour or suspicion?’
‘That’s the queerest part of the whole thing. I never heard of mining operations or anything of the sort in these parts, did you?’
‘Perhaps the French Government – ?’
‘I shouldn’t think so – anyhow, we’ll find out sooner or later. Let’s get out now.’
They climbed from the Sun Bird, and he made to shut the door.
‘No, wait a minute. We’ve forgotten –’
Margaret dashed back inside and reappeared with a wriggling bundle of fur.
‘Poor Bast,’ she said. ‘We nearly left her to a dreadful fate. She’ll have to come along with us.’
The cat mewed. Mark gave it a look of mild disapproval. It would probably be a damned nuisance; however, one could scarcely leave it to starve.
‘Come on,’ he said.
The ramp, an inclined ledge running along the face of the wall, was steep, but of no great length. A few minutes climbing was sufficient to bring them to its levelled-off end in front of the cave mouth, and to show them a long tunnel illuminated at intervals by lamps similar to those over the water. Mark lingered only to cast down one regretful glance on the Sun Bird where she lay, glittering like a silver shuttle, at the water’s edge. Then they turned their backs on the lake and entered the tunnel together.
For a time they walked in silence, each busy with thoughts. The floor had been smoothed and was dry, which made for easy progress. Both made efforts to convince themselves that it had an upward trend, but they were bound to admit that so slight a gradient would mean that many days walking lay between them and the surface. The monotonously echoed trudge of their feet began to get on Margaret’s nerves. She glanced at the severely thoughtful expression on Mark’s face.
‘Well, what are you making of it?’ she asked at length.
He started out of his reverie.
‘Not much,’ he admitted. ‘I’m puzzled by that lake. Why on earth should anybody want to illuminate a lake? There weren’t even any boats on it.’
‘They may have been washed away.’
‘But there would have been mooring rings or something to show that they’d been there.’ He shook his head. ‘And that ramp … It didn’t stop just below the surface; it went on and down, a long way. I wonder if – ?’
‘What?’
‘Well, perhaps it has only just become a lake – it’s more easy to understand that a huge, dry cavern should be lit like that. Suppose that the water from above has only recently broken through and flooded it?’
‘Yes, that might be possible – I wonder – ?’
They tramped on for a time without speaking. Mark’s mind returned to the problem of the inhabitants. Where were they? And what manner of people could they be? Neither the corridor nor the lake had been lighted without purpose; yet there was no sign nor sound of a creature other than themselves. Their entire absence was becoming more uncanny.
The tunnel began to turn to the left. He consulted a pocket compass and learned that they were travelling north. It could scarcely be called a useful discovery, but he was glad to know it; the tunnel must communicate with others, and the compass would at least serve to prevent them travelling in circles. It was not long before they came to a choice of ways; a tunnel, exactly similar to the one they were in, cut across at right angles.
‘Toss up for it,’ suggested Margaret.
Mark, after a careful inspection, came to the conclusion that hers was as good a way of choosing as any other.
‘Heads, we go forward; tails, we turn.’
The coin spun and fell to the ground with a tinkle.
‘Heads it is,’ cried Margaret, looking down at the profile of Queen Elizabeth the Second. The way beyond the crossing differed from their earlier tunnel only in having a slight breeze which blew in their faces and grew perceptibly cooler as they advanced. It carried, moreover, the tang of some faintly familiar, though unplaceable, odour. They hastened their steps at the suspicion that the monotony of bare tunnels was soon to be broken. Keeping straight ahead, disregarding the smaller side tunnels which now became more frequent, they made for the source
of the draught. The air became still damper and fresher. It carried a suggestion of growing plants. Nevertheless, the sight which met them when they turned the final corner took them by surprise.
As if by common consent they stopped on the threshold of a great cavern, staring in speechless amazement. At last:
‘Mushrooms!’ said Margaret, feebly.
Far, far up in the roof the familiar globes were shedding their soft rays, but this time they fell on to neither barren rock nor water; they served to show a nightmare picture. From a bed of dark, soft loam which covered the ground grew a huge crop of queer forms. Most massive, and most noticeable were mushrooms. Monstrous mushrooms which balanced umbrellaed heads larger than wagon wheels upon thick, white trunks, eight or nine feet high. Taller still reached the sleek cones of more slender fungi, yellow, red or steely grey. Closer to the ground, among the pillar-like mushroom columns, grew great globular plants, some brick red, some dappled brown and cream, some white, like familiar puff-balls, giantly inflated. Varie-hued tendrils, fat, like gorged serpents, lay here and there, contorted and looped by their efforts to find growing space. Shapes which, but for the virulence of their colouring, might have been marrows contrived to struggle for a compressed existence between the trunks and the swelling balls. There was chaos of line and form, but still worse of colour. The brushes of a distraught painter might have dabbed into the impossible scene the sudden splashes of purples, greens, reds and yellows.
The sight of Mark’s wide-mouthed astonishment made Margaret laugh.
‘But it’s incredible – fantastic,’ he objected.
She nodded. ‘Do you know what it reminds me of? Pictures in story books when I was a kid – only this technique’s more modern. Enormous toadstools under which gnomes lived. There was one just like that in one book.’ She indicated a particularly arrogant scarlet fungus, spotted with white. ‘But I never thought I should see the real thing. Let’s go nearer.’
They stepped from the firm rock border on to the loam, and examined the nearest mushroom curiously. Mark opened his knife and prodded it. It was quite soft. He sliced off a piece of the trunk and tasted it cautiously. The flavour was coarse, and the matter fibrous, nevertheless: