I will here resume my own narrative.

When I came to myself I was dazed and aching, but, so far as I could discover, there were no bones broken. The curious part about it was the rapidity with which I recalled my fall into the cavern. When I found I could move my limbs freely I sat up, and discovered that I was in a small cabin on board a steamer. I stood up and stretched myself. I was feeling weak and ill, but that would pass off I thought. A minute’s speculation decided me that I was on board the Fiona, in which case I was shanghaied.

I knew that if I valued my life I must act at once. I opened the door of the cabin, and was surprised to find that it was unlocked. Then I crept cautiously in the shadows of the dawn up the companion-ladder to the deck. Though I heard voices I could see no one close to me. I stole along the deck and listened. The voices were talking quite freely in German. Where could we be? And, more important still, where were we going?

I looked around me, and saw that we were steaming slowly down a narrow loch, surrounded by mountains which stretched right down to the shores. I looked across the deck and almost shouted out in my surprise. For there, moving gracefully alongside of us, was a submarine. There were two officers on the deck of the submarine chatting with Hilderman and Fuller, who were leaning over the rail of the Fiona. A submarine! A German submarine in a peaceful Scottish loch! Then this was the secret base we had discussed. I looked up at the wheel-house. In front of it was the very searchlight, with its curious condenser that I had seen in the cavern.

What could it mean? I decided to slip overboard unseen, if possible, swim to the shore, and get back over the rocks to the mouth of the loch, and give the alarm if I should be fortunate enough to attract the attention of any passing steamer.

But suddenly an idea struck me. I crept quickly up the ladder to the deckhouse, threw my arms round the man at the wheel, flung him down on to the deck, and swung the wheel round with all the strength I had in me. There was a dull, crunching sound as the yacht lurched round. A groaning shiver shook her, and, if I may be pardoned the illustration, it felt exactly as if the ship were going to be sick. There were hoarse cries from the men, and as the Fiona righted herself I looked astern. There was a frothy, many-coloured effervescence of oil and water.

The submarine had disappeared! The yacht was nearing the head of the loch. It was now or never. I made a dash for the side, but Fuller was before me. He tripped me up, and I fell heavily to the deck, bruising myself badly and giving my head a terrible bump. I put up my arm in a last feeble attempt to defend myself. Fuller’s hands closed on my throat and nearly choked the life out of me, and as I sank back, struggling for breath, a loud cry rang out from Hilderman.

“Guernstein! Guernstein!” he yelled.

Fuller let me go and ran to Hilderman. I lifted myself on my elbow. Somehow or other I would crawl to the side, and get away before he came back to finish me, but as I looked out over the stern I was rooted to the spot by the sight that met my eyes. Or was I deluding myself with the fantastic delirium of a dying man? Not four hundred yards away was a motor-boat. It was Hilderman’s Baltimore II., and in it were Myra, my poor Myra, and Garnesk and Angus, all wearing motor-goggles. But, strangest of all, a British destroyer was puffing serenely behind them. No, I must be dreaming. Garnesk had told me he was sending glasses for Myra. He had mentioned his connection with the naval authorities. This must be the nightmare of death-agony.

Then Fuller rushed up the wheel-house ladder and jumped on to the searchlight platform. Suddenly there flashed out on the grey light of the dawn a vivid green ray. So, then, the mystery was solved—but, alas! too late. The green ray was produced by a searchlight, and every man on the destroyer would be blind. I looked back, and as I did so I remembered, with an uncanny distinctness, old General McLeod’s words, “The rock came to me.” The warship seemed suddenly to grow double its size, and then double that, and so on, growing bigger and bigger until it appeared to fill the entire loch, and spread out the whole length of the horizon. I could even see a gold signet-ring on the finger of a young officer on the bridge. I looked round at the details of the boat; it stood out in amazing clearness. If one man on that ship, hundreds of yards away, had opened his mouth I could have counted his teeth. Suddenly I gasped with astonishment as I awoke to the fact that every man on board the destroyer was wearing motor-goggles! I had no time to speculate about this new surprise, for then the Fiona, left to her own devices, suddenly crashed ashore. The ship shook and shivered, and Fuller was thrown on his face beside the searchlight, and as I looked again the destroyer had resumed its normal proportions.

Then the crew of the Fiona rushed about the deck in mad terror, until, evidently at the wise suggestion of one of their number, they decided to wait calmly and give themselves up. Hilderman, closely followed by Fuller, sprang ashore, and made for the mountains. Half a dozen shots rang out from the destroyer, and a rifle bullet checked Fuller’s progress before he had gone more than a few yards.

Hilderman, however, managed to reach the shelter of a ridge of rock, and I watched him as he scuttled up the mountain side, and made straight for a long grey rock which protruded from the foot of a steep crag. And as I looked, and saw him go to the rock and open a door in it, I realised that it was really a great, grey, lean-to shed, cunningly concealed. Hilderman had scarcely opened the door when a huge, dark shadow seemed to fall out of the shed and envelop him. It was Sholto. Blind, and half-mad with fury, he sprang at Hilderman’s throat with the unerring aim of his breed. The wretched man staggered and fell, and Sholto——.

I turned away from the sickening sight, and looked over the side, and saw Myra standing up, waving to me, as they drew alongside the wrecked Fiona.

And then I’m afraid I must have fainted.

I lay on the sofa in Myra’s den, and Myra—God bless her!—was kneeling beside me. Sholto was with us too, looking incredibly wise in a pair of motor-goggles.

“So you see, darling,” said Myra, “the glasses cured me completely, and I can see just as well as ever.” And I shall not repeat what I said in reply to such glorious news.

“Tell me, dear,” I asked shortly, “what exactly happened with Dennis? I haven’t quite got that.”

“Well, he saw me on my way to Glasnabinnie,” she explained, “and was determined to follow. He couldn’t find a boat of any kind, so he swam! Angus saw him in the water and ran and told daddy. When they found there was no boat they went and fetched the one on the loch, carried it down to the sea, and called Hamish. Then they pulled across. Then, you see, when Dennis had his heart attack, I thought he was only pretending. I thought he saw that we should never be able to get away again, and that if he pretended to be dead they would leave us alone. So I followed his lead. I was terribly frightened when I couldn’t make him answer me after they had gone, but before I could do anything daddy and the men arrived. Angus stopped with me, and told me where the Fiona had gone. We took the Baltimore because she is much faster than our boat. He must have been a duffer to lose that race we had. And then daddy and Hamish took Dennis—I refuse to call him Mr. Burnham after this—and brought him here and sent for Dr. Whitehouse.”

“I’m thankful he’s out of danger,” I said fervently.

“But the doctor says he must take it very, very gently for a long time, and he won’t be able to walk much for months. Did he know he had this heart trouble?”

I had scarcely finished explaining the extent of Dennis’s heroism when Garnesk arrived.

“Hilderman’s dead!” he said. “He made a full confession. It seems he is a German, and his name’s von Hilder. He has lived most of his life in America. He is a brilliant physicist, and has done some big things with electricity and light. He was here to prepare the submarine base you found, and he also got on with a new invention—The Green Ray. Of course he didn’t give the secret of that away, but we have the searchlight, and I have already tumbled to it partly. It is practically a new form of light.

“It is formed by passing violet and orange rays through tourmaline and quartz respectively. The accident to Miss McLeod was their first intimation of its blinding properties, and to the end he knew nothing about the suffocation part of it. I find by experiment that when the two rays are switched on simultaneously the air does not become de-oxygenised, but when you put the violet ray first it does, and it remains so until the orange ray is applied. The effect that Hilderman imagined, and succeeded in producing, was a ray of light which should so alter the relative density of the air as to act as a telescope. He’s done it, and it’s one of the finest achievements of science. However, I have a piece of wonderful news for you.”

“What is it?” we both demanded at once.

“The Secret of the Green Ray is ours, and ours alone. Hilderman has admitted that the reason why they did not clear it out at the first sign of suspicion was that, in their final calculations, they were unsure of their figures. That means, put popularly, that though he knew what he was trying to do, and how he meant to do it, the actual result was something of a fluke. It very often is with inventors. They had no drawings that they could rely on to make another searchlight by, so they were bound to take the whole thing back with them. They could send no figures, because the relative distances and other quantities baffled them. They could not take the searchlight back in pieces, because if any piece had been broken they might not have been able to reconstruct the proportions with critical accuracy, as we say. So what was to have been Germany’s hideous weapon of war is now ours. We have a searchlight which acts as a telescope, which will pierce the deepest fog, and which will dispel the most ungodly poisonous gases ever invented. You can see for yourself that no gas could make headway against the atmosphere you encountered the other day. Armies and navies will be absolutely powerless to advance against it. The green ray is the fourth arm of military power. So you see what you’ve done for your country, you lucky dog!”

“I!” I cried. “I like that! I’ve had less to do with it than anyone. What about you, eh?—coming running up with a gunboat at the critical moment. How did you manage that?”

“Well,” he replied, “as soon as I was in the train on my way back I solved the problem of the fateful hour—with your help, of course. You pointed out that only then was the whole of the gorge flooded with sunshine. Now, it struck me that, if it were not electricity, it would be heat or some other form of light. Then it flashed into my mind that if it were done from a searchlight possessed of some devilish properties the light would not be visible, but the properties would continue to act. VoilÀ! Then I had already—also with your help—had some doubt of von Hilder; and the hut was the place from which a searchlight would operate on the river. As soon as I got out of the train I taxied to my naval chief, under whom I am working throughout the war, and simply paralysed him with the whole yarn. I pitched him such a tale that he got through to the gunboat to stand by at Mallaig. They were at Portree, nice and handy. I rushed and got the glasses done for the men, picked up the destroyer at Mallaig, and made round here to find out what was happening. Then we sighted Miss McLeod and Angus, and you know the rest. Miss McLeod refused to take the shelter the warship offered, and Angus refused to leave her, so I stayed with them. We acted as pilot-boat, and there you are. That’s the lot! Are you satisfied?”

“I’m satisfied, old man,” I said, holding out my hand. “Some day I’ll try and tell you how satisfied.”

“Oh, that’s all right,” he laughed, and left us in great spirits to return to the searchlight.

And so I was left alone with Myra, who a month ago became my wife. For my services rendered in connection with the remarkable affair I received an appointment in the Naval Intelligence Department, while many of our recent successes on land and on sea have, though the truth has been withheld from the public, been due to the employment of The Green Ray.

The End.

Printed in Great Britain by Wyman & Sons, Ltd., London and Reading.

TRANSCRIBER’S NOTE:

Minor changes have been made to correct typesetter’s errors; otherwise, every effort has been made to remain true to the author’s words and intent.