So it was arranged that we should have an afternoon on the sea and a morning's fishing on the loch. Garnesk fell in with the idea readily.

"It will do you good," he declared. "You won't be feeling too frisky in the morning after your adventure this afternoon."

As it turned out he was quite right, for I awoke in the morning with a slight headache and a tendency to ache all over. So we fished the loch in a very leisurely fashion for an hour or two, and after lunch the four of us went up to Kinlochbourn. We took a tea-basket with us, and very nearly succeeded in banishing the green ray altogether from our minds. I had taken my Kodak with me, and we ran in shore, and otherwise altered our course occasionally in order to enable me to record some choice peep of the magnificent scenery. When we got back to the lodge we were all feeling much the better for the outing. After dinner Myra, who had taken the greatest interest in the photographs, although, poor child, she could not see what I had taken, and would not be able to see the result either, was anxious to know how they had turned out.

"I should love to know if the snapshots are good," she said, "particularly the one at Caolas Mor. Develop them in the morning, Ronnie, won't you? If you don't you'll probably take them away, and forget all about them."

Garnesk looked at me. He was always on the qui vive for any opportunity to give Myra a little pleasure. He felt very strongly that she must be kept from worrying at all costs.

"Why not develop them now, Ewart?" he suggested.

"Certainly," I said, "if everybody will excuse me."

"Dad's in the library," Myra replied, "but everybody else will come with you if you ask us nicely. Besides, I shall have to tell you where everything is. There's plenty of room for us all."

"Right you are," I agreed readily, and went out to get a small folding armchair from the verandah. We went up to the dark-room at the top of the house, and Myra sat in the corner, giving me instructions as to the position of the bottles, etc. I prepared the developer while Garnesk busied himself with the fixing acid.

"Now we're ready," I announced, as I made sure that the light-tight door was closed, and lowered the ruby glass over the orange on Myra's imposing dark-room lamp; she believed in doing things comfortably; no messing about with an old-fashioned "hock-bottle" for her. I took the spool from my pocket and began to develop them en bloc.

"How are they coming along?" Myra asked, leaning forward interestedly.

"They're beginning to show up," I replied; "they look rather promising."

"It's rather warm in here," said the girl presently; "do you think it would matter if I removed my shade, Mr. Garnesk?"

"Not if you put it on again before we put the light up," the specialist answered. Myra took off the shade and the heavy bandage with a sigh of relief, and leaned her elbow on the table beside her.

"There's a glass beaker just by your arm, dear," I said; "just a minute and I'll put it out of reach."

"All right," said Garnesk, moving forward, "I'll move it; don't you worry."

But before he could reach the table there was a crash. The beaker went smashing to the floor. I turned with a laugh, which died on my lips. Myra was standing up with her hand to her head.

"What is it, darling?" I cried, dropping the length of film on the floor. Garnesk made a grab for the shade. Myra gave a short, shrill little laugh, which had a slightly ominous, hysterical note in it.

"Don't be alarmed, dear," she said quietly, in a curiously tense voice, "I can see!"



CHAPTER XII.

WHO IS HILDERMAN?

I must admit that I was so delighted to find that Myra had recovered her sight that I very nearly made what might have been a very serious mistake. I gave a loud shout of triumph and made a dive for the light, intending to switch it on. This might, of course, have had a very bad effect upon my darling's eyes, but fortunately Garnesk darted across the room and knocked up my arm in the nick of time.

"Not yet, Ewart, not yet," he warned me. "We must run no risks until we are quite sure."

"But, Ronnie, I can see quite well," Myra declared delightedly. "I see everything just as easily as I usually can by the light of the dark-room lamp."

"Still, we won't expose you to the glare of white light just at present, Miss McLeod," said Garnesk solemnly. "We must be very careful. Tell me, how did your sight return, gradually or suddenly?"

"Suddenly, I think," the girl replied. "I took off the shade and laid it down, and then when I looked up I could distinctly see the lamp."

"Immediately the shade was removed?"

"No," she answered, "not just immediately. You see, I was looking at the floor, which is so dark, of course, that you couldn't see it in the ordinary way. Then as soon as I looked up I could see the lamp. For a moment I thought it was my imagination, but when I found I could see Ron stooping over the developing-dish I knew that I was all right again."

"This is very extraordinary, you know," said Garnesk. "Can you count the bottles on the middle shelf?"

"Oh, yes!" laughed Myra, "I can make them out distinctly. Of course, I know pretty well what they are, but in any case I could easily describe them to you if I'd never seen them before."

"What have I got in my hand?" the specialist queried, holding his arm out.

"A pair of nail-clippers," Myra declared emphatically, and Garnesk laughed.

"Well," he said, "you can obviously see it pretty well; but, as a matter of fact, it's a cigar-cutter."

"Oh! well, you see," the girl explained airily, "I always put necessity before luxury!"

So then the oculist made her sit down again and questioned and cross-questioned her at considerable length.

"I'm puzzled, but delighted," he admitted finally. "It's strange, but it is at the same time decidedly hopeful."

"I suppose it means that she will always be able to see in a red light at any rate?" I suggested.

"Probably it does," he agreed, "and, of course, her sight may be completely restored. There is also a middle course; she may be able to see perfectly after a course of treatment in red light. I will get her a pair of red glasses made at once. We can see how that goes. But I feel that it would be advisable to introduce her to daylight in gradual stages, in case of any risk."

"Oh, if we could only find poor old Sholto!" Myra exclaimed eagerly. Garnesk turned to her with a look of frank admiration.

"You're a lucky young dog, Ewart," he whispered to me, "by Jove you are!"

So Myra graciously, but a little regretfully I think, placed herself in the hands of the young specialist and replaced her shade. Then we left the dark-room, allowing the films to develop out on the floor, and went downstairs. We took her out on to the verandah and removed the shade for a moment, but the chill air of the highland night made her eyes smart after their unaccustomed imprisonment, and we gave up the experiment for that night.

As Garnesk and I bathed together in the morning we were both brighter and more cheerful than we had been since his arrival.

"I shall catch the train from Mallaig," he declared. "Can you take me in and meet your friend without having long to wait?"

"If you insist on going," I replied, "I can get you there in time to meet him and you will have an hour or more to wait for your train."

"Oh, so much the better! We can tell him everything and give him all the news in the interval."

"Are you still determined to go?" I asked.

"Yes," he said, "I must go. It will be necessary for me to make one or two inquiries and get a pair of glasses made for Miss McLeod."

"I shall be very sorry to lose you, Garnesk," I said earnestly. "Don't you think you could write or wire for the glasses? You see, if we have come to the conclusion that this green ray is some chemical production of Nature unassisted there isn't the same reason for you to leave us."

"No, that's true," he agreed, "but we were both a bit scared yesterday, old chap, and the more I think of this dog business the less I like it. It was mere conceit on my part that made me say it was bound to be some natural phenomenon merely because I couldn't understand how the effect could have been humanly produced."

"Perhaps," I suggested, "our best course would be to keep an open mind about the whole thing."

"Yes," he replied, "I'm with you entirely. And in that case my going away is not going to aggravate the effects of a natural phenomenon, while it may restrain the human agency by removing the necessity for further activity."

"Well, that's sound enough," I acquiesced; "but I shall hear from you, I hope?"

"Of course, my dear fellow," he laughed, "we're in this thing together. You'll hear from me as often as you want, and who knows what else besides. I have no intention of dropping this for a minute, Ewart. But I think I can do more if I am not on the spot. We're agreed that my presence here may be a source of danger to you all."

"Yes," I said, "I think yours is the best plan. What do you propose to do?"

"Well, to begin with, I shall devote an hour or two to knocking our panic theory on the head."

"You mean the natural phenomenon idea?"

"Precisely," said he. "I don't think that it will be able to exist very long in the light of physical knowledge—not that that is a very powerful light, but it should be strong enough for our purpose. As soon as I have convinced myself that our enemy is a mere human being I shall take such steps as I may think necessary at the time. Then, of course, I shall acquaint you with the steps that I have taken, and we shall work together and round up our man, and, figuratively speaking, make him swallow his hideous green ray."

"What sort of steps do you mean?" I asked.

"Well, that all depends," my friend answered, "on what sort of man we have to deal with. But it will certainly include providing ourselves with the necessary means of self-defence, and may run to calling in the assistance of the authorities."

"I'm not sure that the presence of the police in a quiet spot like this might not have a disastrous effect on our plans," I pointed out.

"I shouldn't worry about the police," he laughed. "I should make for the naval chaps. I'm rather pally with them just now; I'm booked up to do some work of various descriptions for the period of the war, and I think if I can give them the promise of a little fun and excitement they would be willing to help."

"Which indeed they could," I agreed readily. "Any attempt our enemy might make to get away from us would probably mean a bolt for the open sea, and a few dozen dreadnoughts would be cheerful companionship."

Garnesk laughed, and we strolled up to the house, putting the finishing touches to our toilet as we went. Shortly after breakfast we made ready for our trip to Mallaig. Myra was very anxious to come with us until I explained that we should have to wait there till we had met Dennis and seen the specialist off. She was naturally sensitive about appearing in public with the shade on, poor child, so she readily gave up the idea.

"I'm very sorry you're going, Mr. Garnesk," said Myra, as she shook hands.

"I shall see you again soon," he replied. "I have by no means finished with your case, and as soon as you report the effect of the glasses I shall send you'll see me come tripping in one afternoon, or else I shall ask you to come down to me."

"It's very good of you to take so much trouble about it," said Myra gratefully.

"Not at all," he responded lightly. "It is a pleasure, Miss McLeod, I assure you."

The old general was still more effusive of his gratitude, and as he waved good-bye from the landing-stage his face was almost comically eloquent of regret.

"By the way," said Garnesk as we passed Glasnabinnie, "don't tell Hilderman much about what has happened. We feel we can trust him, but you never know a man's propensity for talking until you know him very well."

"Right," I agreed. "I'll take care of that. We can't afford to get this talked about. It would be very painful for Myra and her father if it became the chatter of the country-side."

"Besides," Garnesk pointed out, "it will be much safer to be quiet about it. If we are dealing with men they will probably prove to be desperate men, and we don't want to run any risks that we can avoid."

"No," said I, "this is going to be quite unpleasant enough without looking for trouble."

So when we arrived in Mallaig and met Hilderman on the fish-table I was careful to remember my companion's advice.

"Ah, Mr. Ewart!" the American exclaimed in surprise, "How are you? And you, Professor? I hope your visit has proved entirely satisfactory. How is Miss McLeod?"

"Just the same, I am sorry to say," Garnesk replied glibly. "There is no sign at all of her sight returning. I can make nothing of it whatever."

"Dear, dear, Professor!" Hilderman exclaimed, with a shake of the head. "That is very bad, very bad indeed. Haven't you even any idea as to how the poor young lady lost her sight?"

"None whatever," said Garnesk, with a hopeless little shrug. "I can't imagine anything, and I'm not above admitting that I know nothing. There is no use my pretending I can do anything for poor Miss McLeod when I feel convinced that I can't."

"So you've given it up altogether, Mr. Garnesk?" Hilderman asked, as we strolled to the station.

"What else can I do?" the oculist replied. "I can't stop up here for ever, much as I should prefer to stay until I had done something for my patient."

"You have my sympathy, Mr. Ewart," said Hilderman in a friendly voice. "It is a terrible blow for you all. I fervently hope that something may yet be done for the poor young lady."

"I hope so too," I answered, with a heavy sigh, but the sigh was merely a convincing response to the lead Garnesk had given me, for, as a matter of fact, I was quite certain that we had found the basis of complete cure.

"Yes," Hilderman muttered, as if thinking aloud, "it is a very terrible and strange affair altogether. Have you had any news about the dog?"

"None whatever," I replied, this time with perfect truth.

"Surely you must suspect somebody, though," the American urged. "It is a very sparsely populated neighbourhood, you know."

"We can't actually suspect anybody, nevertheless," said I. "On the one hand, it may have been an ordinary, uninteresting thief who stole the dog with a view to selling him again. On the other hand——"

"Well," said Hilderman with interest, as I paused, "on the other hand?"

"It may have been someone who had other reasons for stealing him," I concluded.

"I don't quite follow you."

"Ewart means," said Garnesk, cutting in eagerly, evidently fearing that I was about to make some indiscreet disclosure of our suspicions, though I had not the slightest intention of doing so, "Ewart means that it may have been someone who regarded the dog as a personal enemy. Miss McLeod informs us that there was a man in the hills, ostensibly a crofter, who disliked Sholto, quite unreasonably. He drove the dog away from his croft and was very rude to Miss McLeod about it. She suspected an illicit still, and thought the fellow was afraid Sholto might nose out his secret and give the show away."

"Ah!" said Hilderman. "An illicit still, eh! Where was this still, or, rather, where was the croft?"

I remembered that Myra had told us it was somewhere up Suardalan way, above Tor Beag, and I was just about to explain, when I felt my friend's boot knock sharply against my ankle. Taking this as a hint and not an accident, I promptly lied.

"It was miles away," I announced readily, "away up on The Saddle. Miss McLeod wanders pretty far afield with Sholto at times."

"Indeed," said the American, "I should think that might be quite a likely explanation, and rather a suitable place for a still, too. I climbed The Saddle some months ago with an enthusiastic friend of mine. We went by water to Invershiel, and then drove up the Glen. I shouldn't like to walk from Invermalluch and back; there are several mountains in between, and surely there is no road."

Evidently our shrewd companion suspected that I had either made a mistake or deliberately told him an untruth, but I was quite ready for him. I had no time to consider the ethics of the matter. I was out to obey what I took to be my instructions, and obey them I did.

"Oh, there are quite a lot of ways of getting there," I replied airily; "but perhaps the easiest would be to take the motor-boat to Corran and walk up the Arnisdale, or follow the road to Corran and then up the river. Miss McLeod has her own ways of getting about this country, though, and she may even know some way of avoiding the difficulties of the Sgriol and the other intervening mountains."

Hilderman looked at me in considerable surprise for a moment.

"You seem to know the district pretty well yourself, Mr. Ewart," he remarked.

"Well, I ought to," I explained; "I was born in Glenmore."

"Oh, I didn't know that," he murmured; "that accounts for it, then." And at that moment we heard the train approaching, and we hurried into the station to meet our respective visitors.

"Fact or fancy?" asked Garnesk in an undertone as we strolled down the platform, Hilderman having hurried on ahead.

"Fancy," I replied. "I took it you wanted me to avoid giving him the precise details."

"Yes, I did," he laughed. "But you certainly made them precise enough. It is better to be careful how you explain these things to strangers."

"Why?" I asked. "If we suspected Hilderman I should be inclined to agree with you that we should feed him up with lies; and if you think it will help us at all to suspect him I'm on at once. But as we both feel that his disposition is friendly and that we have no cause to doubt him, what is your reason for putting him off the scent every time? I know you well enough by this time to feel sure that you haven't been making these cryptic remarks for the sake of hearing yourself speak."

"Here's the train," he said. "I'll tell you later."

I looked along the carriages for Dennis, but I had evidently missed him, for as I turned back along the platform I found him looking round for me, standing amid the melee of tourists and fisherfolk, keepers and valets, sportsmen and dogs, which is typical of the West Highland terminus in early August, and which seemed little affected by the fact that a state of war existed between Great Britain and the only nation in the world which was prepared for hostilities.

"Well, old man," I greeted him as we shook hands heartily. "You got my wire, of course. I hope you had a decent journey."

"Rather, old chap, I should think I did!" he replied warmly. "Slept like a turnip through the beastly parts, and woke up for the bit from Dumbarton on. I also had the luck to remember what you said about the breakfast and took the precaution of wiring for it. Here I am, and as fit as a fiddle."

"That's great!" I exclaimed cheerily, for Dennis's bright attitude had exactly the effect on me that it was intended to have—it made me feel about twenty years younger. "This is Mr. Garnesk, the specialist, who very kindly came from Glasgow to see Myra. Mr. Garnesk—Mr. Burnham."

The two shook hands, and the oculist suggested lunch. We left the station to go up to the hotel, but we saw Hilderman and his newly arrived friend—the same man who had seen me taking Myra up to London—walking leisurely up the hill in front of us. Garnesk took my arm.

"Steady, my boy, steady," he said quietly. "We don't want to be overheard giving the lie to your dainty conversation of a few minutes ago. Isn't there anywhere else we can lunch, because they are evidently on the same tack?"

"Yes," I replied, turning back, "there's the Marine just behind you. That'll do us well. Then we can come out and talk freely where there's no chance of our being overheard."

So we lunched at the Marine Hotel, after which we strolled round the harbour, along the most appalling "road" in the history of civilisation, popularly and well named "the Kyber." Safely out of earshot, I made a hurried mental precis of the events of the past few days, and gave Dennis the resultant summary as tersely as I could.

"I'm very glad you had Mr. Garnesk with you," said Dennis at last, with a glance of frank admiration at the young specialist.

"Not so glad as I am," I replied fervently. "What I should have done without him heaven only knows. I can't even guess."

"Oh, nonsense!" cried Garnesk, in modest protest. "I haven't been able to do anything. Our one advance was a piece of pure luck—the discovery that Miss McLeod could see by the light of a red lamp. We have decided to keep that quite to ourselves, Mr. Burnham."

"Of course," agreed Dennis, so emphatically that I laughed.

"Why so decided, Den?" I asked, for I felt that I should like to climb to the topmost pinnacle of the highest peak in all the world and shout the good news to the four corners of the earth.

"I'm not a scientist, Ron," Dennis replied. "That may account for the heresy of my profound disbelief in science. I wouldn't cross the road to see a 'miracle.' The twentieth century is uncongenial to anything of that sort. Take it from me, old chap, there's a man at the back of this—not a nice man, I admit, but an ordinary human being to all outward appearances—and when we catch a glimpse of his outward appearances we shall know what to do."

"Yes, when we do," I sighed.

"You mustn't let Ewart get depressed about things, Mr. Burnham. He very naturally looks at this business from a different standpoint. With him it is a tragic, mysterious horror, which threatens the well-being, if not the existence, of a life that is dearer to him than his own."

"I'll look after him," said Dennis, with a grim determination which made even Garnesk laugh.

"When you two precious people have finished nursing me," I said, "I hope you'll allow me to point out that that very reason gives me a prior claim to take any risks or run into any dangers that may crop up from now on. If there is any trouble brewing, particularly dangerous trouble, then it is my place to tackle it. I am deeply grateful to you fellows for all you have done and are doing and intend to do, but the nursing comes from the other side. I can't let you run risks in a cause which is more mine in the nature of things than yours."

"I fancy," said Dennis, "that even your eloquent speeches will have very little effect when it comes to real trouble. If danger comes it'll come suddenly, and we shall be best helping our common cause by looking after ourselves."

"Hear, hear," said Garnesk, and I could only mutter my thanks and my gratitude for the possession of two staunch friends.

"To get back to business," I said presently, "why did you want me to bluff Hilderman like that?"

"Because," said Garnesk slowly, "I'm not sure that Hilderman is the man to take into our confidence too completely. It's not that I don't trust the man, but he looks so alert and so cute, and has such a dreamy way of pretending he isn't listening to you when you know jolly well that he is, that I have a feeling we ought to be careful with him."

"Very much what Dennis said about him the first time he saw him. But if you don't suspect him, and he is a very cute man, why not trust him and have the benefit of his intelligence?"

"How would you answer that question yourself, Ewart?" the specialist asked quietly.

"Oh," I laughed, "I should point out that his cuteness may be the very reason that we don't suspect him."

"Precisely," Garnesk agreed; "and that is partly my answer as well."

"And the other part?" put in Dennis quietly.

"Well, it's a difficult thing to say, and it's all conjecture. But I have a feeling that Hilderman is not what he says he is. He has a knack of doing things, a way of going about here, that gives me the impression he is employing his intelligence, and a very fine intelligence it probably is, all the time. I don't think he is retired at all. There's a restless energy about the fellow that would turn into a sour discontent if his mind were not fully occupied with work which it is accustomed to, and probably enjoys doing."

"Have you anything to suggest?" I asked.

"I have an idea," he replied; "but I haven't mentioned it because it doesn't satisfy me at all. I have an idea that the man is some sort of detective hard at work all the time. But I can't imagine what sort of detective would take a house up here and keep himself as busy as Hilderman appears to be over some case in the neighbourhood. I can't imagine what sort of case it can be."

"What about a secret German naval base in the Hebrides?" I suggested. "It's not by any means impossible or even unlikely that the Germans have utilised the lonely lochs and creeks to some sinister purpose. Many of the lochs are entirely hidden by surrounding mountains, which come right down to the edge of a narrow opening, and make the place almost unnoticeable unless you happen to be looking for it."

"There's something in that, certainly," Garnesk agreed; "but we must remember he's been here since May. Surely our precious Government would have managed to find what they wanted, and clear it out by this time. Then again, did they suspect the base, or did they have a general idea that war was coming so far back as May?"

"As to the war," Dennis put in, "we don't really know when the authorities had their first suspicions."

"No," said I; "but I fancy it was not a very definite suspicion until after the Archduke was assassinated. But look here, Garnesk, just let us suppose Hilderman really is a Government detective in the guise of an American visitor. Wouldn't he be just about the man we want, or do you think it would make too much stir to take him into our confidence?"

"Far too much," Garnesk replied emphatically. "It's not that he would talk; but if he has been here all this time his opponents have got wind of him long before this, and his arrival on the scene in connection with our case would give any suspicious character the tip to bolt. I should advise keeping in touch with Hilderman, learn as much as you can about him, and be ready to run to him for help if you come to the conclusion that he is the man to give it."

We sat down among the heather at the foot of the Mallaig Vec road, and looked out over the harbour.

"Don't turn your heads," said Dennis quietly, "but glance down at the pier."

"Yes," said Garnesk in a moment, "he seems to be as interested in us as we are in him."

Hilderman and his friend were standing on the end of the pier watching us through their field-glasses.



CHAPTER XIII.

THE RED-HAIRED MAN.

"I'll send the glasses at once," said Garnesk, as the train steamed out of the station. Dennis and I stood on the platform and watched him out of sight.

"He seems a good fellow," said Dennis.

"Splendid!" I agreed readily. "He's exceeding clever and wide-awake, and very charming. What we should have done without him heaven only knows. I fancy his visit saved the entire household from a nervous collapse."

"We've no time for collapses, nervous or otherwise," Dennis replied. "We shall want our wits about us, and we shall need all the vitality we can muster. But at the same time I don't think there is any cause for nerves. You're not the sort of man, Ron, to let your nerves get the better of you in an emergency, especially if we can prove that our enemy is a tangible quantity, and not a conglomeration of waves and vibrations."

"Hilderman and his friend appear to be waiting for us," I interrupted.

"You may as well introduce me," said Dennis. "I'd like to meet the man. Who is his friend, do you know?"

"Haven't the remotest idea," I replied. "I have seen him once before, but that is all. I don't know who he is."

"Is he staying with Hilderman, or does he live in the neighbourhood?"

"That I couldn't tell you either," I said. "I'm sure he doesn't live anywhere near Invermalluch."

As we strolled out of the station Hilderman and his companion were standing chatting by the gate which leads on to the pier. As we approached, Hilderman turned to me with a smile.

"Ah, Mr. Ewart," he exclaimed, "your friend has left you, then. I hope you won't let his inability to help Miss McLeod depress you unduly. While there's life there's hope."

"I shall not give up hope yet awhile, anyway," I answered heartily.

"May I introduce my friend Mr. Fuller?" he asked presently, and I found myself shaking hands with the round-faced little man, who blinked at me pleasantly through his glasses. I returned the compliment by introducing Dennis.

"On holiday, Mr. Burnham?" asked the American. Dennis was so prompt with his reply that I was convinced he had been thinking it out in the meanwhile.

"Well, I hardly know that I should call it a holiday," he replied immediately. "I have just run up to say good-bye to Ewart before offering my services to my King and country. We had intended to join up together, but he has, as you know, been detained for the time being, so I am off by myself."

"We are very old friends," I explained, "and Burnham very decently decided to come here to see me as I was unable to go south to see him."

"Never mind, Mr. Ewart," said Hilderman. "I guess you'll be able to join him very soon. I wish you luck, Mr. Burnham. I suppose it won't be long before you leave."

"He's talking of returning to-morrow," I cut in. "I wish you'd tell him it's ridiculous, Mr. Hilderman. Fancy coming all this way for twenty-four hours. He must have a look round, to say nothing of his stinginess in depriving me of his company so soon."

"Well, I can quite understand Mr. Burnham's anxiety to join at the earliest possible moment," he answered. "But I've no doubt Lord Kitchener wouldn't miss him for a day. I think he might multiply his visit by two, and stop till Wednesday, at any rate. Ah, here's the Fiona!"

I looked out to the mouth of the harbour, and saw the steam yacht, which was in the habit of calling at Glasnabinnie, gliding past the lighthouse rock. I was about to make some comment on the boat when Hilderman forestalled me.

"How are you going back?" he asked.

"In a motor-boat," I replied. "I am afraid Angus is getting weary of waiting already."

"I'm sure Mr. Fuller would be delighted to have you fellows on board. Why not let your man take Mr. Burnham's luggage to Invermalluch, and come to Glasnabinnie on the Fiona? You can lunch with me, and when you tire of our company I will run you across in the Baltimore. Eh? What do you say?"

"I shall be delighted, of course," his companion broke in.

I hesitated for a moment, and glanced at Dennis. His face obviously said, "Accept," so I accepted.

"Thank you," I said; "we shall be very pleased. It will be more jolly than going back by ourselves."

"Good!" cried Hilderman, "and I can show you the view from my smoking-room. I hope it will make you green with envy."

So I gave Angus his instructions, and the four of us waited at the fish-table steps for the dinghy to come ashore from the yacht. She was not a particularly beautiful boat, but she looked comfortable and strong, and her clumsy appearance was accentuated by the fact that her funnel was aft a commodious deck dining-saloon, on the top of which was a small wheel-house. Myra had been right, as it turned out; she was a converted drifter. The two men who came in to pick us up wore the usual blue guernsey, with S.Y. Fiona worked in an arc of red wool across the chest. They were obviously good servants and useful hands, but there was none of that ridiculous imitation of naval custom and etiquette which delights the heart of the Cotton Exchange yacht-owner. We boarded the Fiona with the feeling that we were going to have a pleasant and comfortable time, and not with the fear that our setting of a leather-soled shoe upon the hallowed decks was in itself an act of sacrilege. We were no sooner aboard than Fuller set himself to play the host with a charm which was exceedingly attentive and neither fussy nor patronising.

"The trivial but necessary question of edible stores will detain us for a few moments," he said. "But we shall be more comfortable here than wandering about among the herrings." So we made ourselves comfortable in deck-chairs in the stern, while the steward went ashore and made the all-important purchases.

"You cruise a good deal, I suppose?" was my first question.

"Yes, a fair amount," our host replied. "I pretty well live on board, you know, although I have a small house further north, on Loch Duich, if you know where that is."

"Mr. Ewart was born up here, and knows it backwards," Hilderman informed him. And we chatted about the district and the fishing and the views until the steward returned, and we got under weigh. I should have liked to have seen the accommodation below, but the journey was a short one, and I had no opportunity to make the suggestion. Dennis was sitting nearest the rail, and there was a small hank of rope at his feet.

"I beg your pardon, Mr. Burnham," said Fuller suddenly. "I didn't notice that rope was in your way." And he learned over and tossed the rope away. As he did so some hard object fell with a clatter from the coil.

"It's not interfering with me in the least," laughed Dennis, and looked down at a large, bone-handled clasp-knife which had dropped in front of him. He picked it up idly, and weighed it in his hand.

"Useful sort of implement," he said.

"Oh, these sailor-chaps like a big knife more than anything," said Hilderman; "and, of course, they need them strong. I daresay that has been used for anything, from primitive carpentry to cutting tobacco. The one knife always does for everything."

We continued our conversation while Dennis idly examined the knife, opening it and studying the blade absently. Presently Fuller, noticing his absorption, began to chaff him about it.

"Well," he laughed, "have you compiled a complete history of the knife and it's owner? If you're ready to sit an examination on the subject I will constitute myself examiner, then we'll find who the knife belongs to, and corroborate or contradict your conclusions."

"It's a very ordinary knife to find on board a boat, I should think," said Dennis.

"Oh come, Mr. Burnham," Hilderman joined in, "you mustn't wriggle out of it. Surely you can answer Mr. Fuller's questions."

"If Mr. Fuller will allow me to put one or two preliminary questions to him," Dennis replied, entering into the spirit of fun, "I am ready to go into the witness-box and swear quite a number of fanciful things."

"Come now, Fuller," chaffed Hilderman. "You must give him a run for his money, you know. He is risking his reputation at a moment's notice. I think you ought to let him ask you three questions, at any rate."

"Fire away, Mr. Burnham," said our host. "I'll give you a start of three questions, and then you must be prepared to answer every reasonable question I put to you, or be branded publicly as an unreliable witness and an incompetent detective."

Dennis puffed at his pipe and smiled, and I was surprised to see that he really was bringing his mind to bear on the trivial problem with all the acuteness he had in him.

"Well, in the first place," he asked, "do you stop in port very often overnight, or for any length of time during the day?"

"I never stop in port longer than I can help," laughed Fuller, "or the owner of that knife would probably take the opportunity of buying a new one, and throwing this old thing away. All the same, I don't see how that is going to help you."

"Ah," said Dennis, in bantering vein, "you mustn't expect me to give away my process, you know. The secret's been in the family for years."

"What's your second question, Den?" I asked.

"Is there a hotel within reasonable distance of your house on Loch Whatever-it-is, Mr. Fuller?"

"Loch Duich?" our host replied. "There's one about six miles by road and eleven or twelve by the sea."

"I don't think I need ask you the third question, then," said Dennis. "You can begin your examination now."

"Now, Mr. Burnham," Fuller commenced, "you quite understand that anything you say will be taken down in writing, and may be used as evidence against you?"

"I assure you I have a keen appreciation of the gravity of the situation," Dennis replied seriously.

"Well," said Fuller, "I'll begin with an easy one—one that won't tax your powers of observation beyond endurance."

"Yes," I urged, "let him down gently. He does his best."

"What profession does the owner of that knife follow?"

Hilderman and I laughed.

"We may as well count that answer as read," he said.

"There's a catch there, Dennis," I warned him. "The legal designation is 'mariner.'"

"I don't think it is," said my friend.

"We won't quarrel about terms," laughed our host graciously. "Sailor or seaman or deckhand will do just as well."

"No," said Dennis, "it won't. The owner of this knife is not a sailor by profession."

"But," Fuller protested, "it must belong to one of my crew, and it is obviously a seaman's knife."

"In that case," Dennis answered, "I think you'll find that you have a man on board who is not a professional seaman in the ordinary use of the term. I'll tell you what I think of this knife, shall I?"

"By all means," urged Hilderman and his friend together, and I began to take a keen interest in this curious discussion, for I could see that Dennis was no longer playing. He turned the knife over in his hand, and looked up at Fuller.

"Mr. Fuller," he said quietly, "the owner of this knife is not a sailor by profession. He is probably a schoolmaster. I can't be sure of that, but I can say this definitely: he is a professional man of some sort, possibly an engineer, but, as I say, more probably a mathematical master. He is left-handed, has red hair, a wife, and at least one child."

I shouted with laughter when I realised how thoroughly my friend had pulled my leg, but I broke off abruptly when Hilderman sat bolt upright, and his chair and Fuller's cigar fell unheeded on to the deck. But in a second they took their cue from me, and roared with laughter.

"Oh, excellent, Mr. Burnham," said Hilderman between his guffaws. "But you forgot to mention that his sister married a butcher's assistant."

"Ah, but I don't admit she did," Dennis protested.

"I'm very much indebted to you for exposing this masquerader," said Fuller. "I shall have the matter inquired into. But seriously, Mr. Burnham, you made one extraordinary fluke in your deductions, which almost took my breath away. I have a man on board with red hair, and when the boat came into the harbour he was working about here. I saw him leave his work to come ashore for us. I shouldn't be at all surprised to find that the knife belonged to him."

"Oh, well," Dennis laughed, "one shot right is not a bad average for a beginner, you know."

"No," said Hilderman, puffing a cloud of smoke, and dreamily following its ascent with his eyes, "not bad at all. Not bad at all."

And then, the joke of the clasp-knife being played out, we admired the scenery, and conversed of less speculative subjects till we arrived at Glasnabinnie.

We were pulled ashore by the man with the red hair, and when our host confronted him with the knife he promptly claimed it.

"I think you won, Mr. Burnham," laughed Fuller, and Dennis smiled in reply. We slid alongside the landing-stage and stepped out, and Dennis's schoolmaster was about to slip the painter through a ring and make the boat fast. But evidently the ring was broken. The man came ashore, and Hilderman began to lead us up the path. But Dennis deliberately turned and watched the sailor. Hilderman and his companion strolled ahead while I stood beside Dennis. The man with the red hair fished among a pile of wire rope, and picked out a small marline-spike. Then he lifted a large stone, held the marline-spike on the wooden planking of the landing-stage, and hammered it in with the stone. Then he threw the painter round it, and made the boat secure in that way.

"Yes," murmured Dennis quietly, as we turned to join the others, "I think I won."

For the man had held the stone in his left hand.



CHAPTER XIV.

A FURTHER MYSTERY.

"Well," said Hilderman, as we caught them up, "what about lunch? After his journey I daresay Mr. Burnham has an appetite, not to mention his excursion into the realm of detective fiction."

"We lunched at Mallaig," I explained, "with Mr. Garnesk before we saw him off."

"Oh, did you?" he asked, with evident surprise. "I didn't see you at the hotel."

"We went to the Marine," I replied, "to save ourselves a climb up the hill."

"We had a snack at Mallaig too," the American continued, "intending to lunch here. Are you sure you couldn't manage something?"

"It would have to be a very slight something," Dennis put in. "But I daresay we could manage that."

"Good!" said Hilderman. "Come along, then, and let's see what we can do."

We strolled into the drawing-room through the inevitable verandah, and though Hilderman was the tenant of the furnished house he had contrived to impart a suggestion of his own personality to the room. The furniture was arranged in a delightfully lazy manner that almost made you yawn. The walls were hung with photographic enlargements of some of the most beautiful spots in the neighbourhood. I remembered what Myra had told me as to his being an enthusiastic photographer, so I asked him about them.

"Did you take these, Mr. Hilderman?"

"Yes," he answered. "These are just a few of the best. I have many others which I should like you to see some time. I always leave the enlarging to keep me alive during the winter months. These are a few odd ones I enlarged for decorative purposes."

"They are beautiful," I said enthusiastically, for they were real beauties, more like drawings in monochrome than photographs. "And you certainly seem to have got about the neighbourhood since your arrival."

"Yes," he laughed, "I don't miss much when I get out with my camera. Most of these were taken during the first month of my stay here."

"These snow scenes from the Cuchulins are simply gorgeous, and surely this is the Kingie Pool on the Garry?"

"Right first time," he admitted, evidently pleased to see his work admired. I thought of Garnesk's suspicion that our American friend was engaged on detective work of some kind, and it struck me that with his camera and his obvious talent he had an excellent excuse for going almost anywhere, supposing he were called upon at any time to explain his presence in some outlandish spot.

"You must have kept yourself exceedingly busy," I remarked in conclusion.

After the meal we adjourned to the hut above the falls. Hilderman certainly had some right to be proud of his view. It was magnificent. We stood outside the door and gazed out to sea, north, south and west, for some minutes.

"You have the same uninterrupted view from inside," said Hilderman, as we mounted the three steps to the door. He held the door open, and I stepped in first, followed by Dennis and Fuller. The window extended the whole length of the room, and folded inwards and upwards, in the same way as some greenhouse windows do. Suddenly I laughed aloud.

"What's the joke?" asked Hilderman.

"This," I said, pointing to a large carbon transparency of a mountain under snow, which hung in the window on the north side. "You've no idea how this has been annoying us over at Invermalluch."

"How?" asked Dennis.

"It swings about in the breeze," I replied, "and it reflects the light and catches everybody's eye. It's a very beautiful photograph, Mr. Hilderman, but, like many human beings, it's exceedingly unpopular owing to the position it holds."

"A thousand apologies, Mr. Ewart," said the American. "It shall be removed at once."

"Oh, not at all!" I protested. "Surely you are entitled to hang a positive of a photograph in your window without receiving a protest from neighbours who live nearly three miles away."

"That's Invermalluch Lodge, then, across the water," Dennis asked.

"Yes," I replied, and we forgot about the transparency, which remained in undisputed possession of a pitch to which it was certainly entitled. We sat and smoked, and looked out at the mountains of Skye and the wonderful panorama of sea and loch, with an occasional glance at the gurgling waterfall at our feet, and presently I picked up a copy of an illustrated paper which was lying at my hand. I turned the pages idly, and threw a cursory glance at the photographs of the week's brides, and the latest efforts of the theatrical press agents, and I noticed, without thinking anything of the fact, that one page had been roughly torn out. I was about to remark that probably the most interesting or amusing picture in the whole paper had been accidentally destroyed, when Fuller leaned across Dennis, and took the paper out of my hands.

"Don't insult Mr. Hilderman's precious view by reading the paper in his smoking-room, Mr Ewart," he said, with a loud laugh. "As a Highlander you should have more tact than that."

Hilderman turned round, and looked from one to other of us.

"What paper is he reading? I didn't know there was one here."

I explained what paper it was, adding, "I quite admit that it was a waste of time when I ought to be admiring your unrivalled view, Mr. Hilderman. I offer you my sincere apologies."

Hilderman threw a quick glance at Mr. Fuller.

"Better give it him back, Fuller," he said. "There is nothing more annoying than to have a paper snatched away from you when you're half-way through it."

Shortly after that Fuller declared that he must be leaving, and asked Hilderman rather pointedly whether he felt like a trip to Loch Duich. I determined to step in with an idea of my own.

"I was going to make a suggestion myself, Mr. Hilderman," I began, "but it doesn't matter if you are engaged."

"Well, I don't know that I'm particularly keen to come with you this afternoon, Fuller," he remarked. "What was your suggestion, Mr. Ewart?"

"I was wondering whether you would come over to Invermalluch with Burnham and me and—er—have a look round with us?"

"Well, if Fuller doesn't think it exceedingly rude of me, I should like to," the American replied, "especially as Mr. Burnham will be leaving you to-morrow, or the day after at latest."

"Incidentally, I don't know how we shall get back without you," I pointed out. "You see, we sent the motor-boat on."

"By Jove, so you did!" Hilderman exclaimed. "Well, that settles it, Fuller."

"I could take them on the Fiona and put them ashore," his companion persisted. Hilderman gave Fuller a look which seemed to clinch the matter, however, for the little man beamed at me through his spectacles, and explained that if he took us in his yacht it would be killing two birds with one stone.

"Still, of course, my dear fellow," he concluded, "you must please yourselves entirely."

So we saw him safely on board the Fiona, and then started for Invermalluch in Hilderman's magnificent Wolseley launch.

"Fuller knows me," he explained, by way of apology. "I go up with him sometimes as often as three times a week, but I gathered that you asked me with a view to discussing the mystery of the green flash, or whatever you call it."

"You're quite right; I did," I replied. "I simply want you to come and have a look at the river, and see what you can make of it."

"Anything I can do, you know, Mr. Ewart," he assured me, "I shall be delighted to do. If you think it will be of any assistance to you if I explore the river with you—well, I'm ready now."

From that we proceeded to give him, at his request, minute details of Garnesk's conclusions on the matter, and I am afraid I departed from the truth with a ready abandon and a certain relish of which I ought to have been most heartily ashamed.

When we stepped ashore at Invermalluch Hilderman looked back across the water.

"If I'd waited for Fuller," he laughed, "I should have been stuck there yet. He's let the water go off the boil or something."

We went up to the house and had tea on the verandah, for the General had taken Myra up Loch Hourn in the motor-boat. After tea we got to business.

"Now that I've had a very refreshing cup of tea," the American remarked, "I feel rather like the mouse who said 'Now bring out your cat' when he had consumed half a teaspoonful of beer! Now show me the river."

"I don't want to sound at all panicky," I said, "but I think I ought to warn you that our experiences at the particular spot we are going to have—well, shall we say they have provided a striking contrast from the routine of our daily life?"

"I'm not at all afraid of the river, Mr. Ewart," he replied lightly. "I should be the last person to doubt the statements of yourself and Miss McLeod and the General, but I am inclined to think the river has no active part in the proceedings."

"You hold the view that it was the merest coincidence that Miss McLeod and the General both had terrible and strange experiences at the same spot?" asked Dennis.

"It seems to be the only sensible view to hold," Hilderman declared emphatically. "I must say I think Miss McLeod's blindness might have happened in her own room or anywhere else, and the General's strange experience seems to me to be the delusion of overwrought nerves. I confess there is only one thing I don't understand, and that is the disappearance of the dog. That's got me beaten, unless it was that crofter."

"We intend to go to the Saddle to-morrow and make a few investigations. I was going by myself," I added cautiously, "but I think I can persuade Burnham to stay and go with me."

"I certainly should stay for that, Mr. Burnham," Hilderman advised. "One more day can't make much difference."

"I'll think it over," said Dennis, careful not to commit himself rashly.

We came to the Dead Man's Pool, and crossed over the river, and began to walk up the other side.

"This is about the right time for a manifestation of the mystery," I remarked lightly, though I was far from laughing about the whole thing.

"Well," said Hilderman, "if we are to see the green flash in operation I hope it will be in a gentle mood, and not pull our teeth out one by one or anything of that sort." Evidently he had little sympathy with our fear of the green ray and the awe with which we approached the neighbourhood of the river.

"Are we going to the right place?" Dennis asked. "I mean the identical spot?"

"That lozenge-shaped thing up there is the Chemist's Rock," I replied, "and the other important place is Dead Man's Pool, which we have just left."

"Miss McLeod went blind on the Chemist's Rock, didn't she?" Dennis inquired.

"Yes," I replied, with a shudder. "She was fishing from it."

"Then suppose we go back to the pool," he suggested. We agreed readily enough, for I had no desire to hang about the fateful rock, and Hilderman for his part seemed to have no faith in the idea at all. I fancy he thought it would make no difference to us in what part of the river we might be, only provided we didn't fall in. So Dennis led the way back, and he was the first to pick his way to the middle of the stream. Hilderman and I were some distance behind. Suddenly we stopped stock-still, and looked at him. He had begun to cough and splutter, and he seemed rooted to the small stone he was standing on in the middle of the stream. In a flash I understood, and with a cry I bounded after him, Hilderman following at my heels.

"It's all right, Ewart," cried Hilderman behind me. "He's only choked, or something of that sort. He'll be all right in a minute."

Dennis had crossed to the centre of the stream by a way of his own, and we ran down to the stepping-stones by which we had come, in order to save the time which we should have been compelled to waste in feeling for a foothold as we went. Every second was of importance, and I fully expected to see Dennis topple unconscious into the pool below before I should be able to save him. I knew what it was exactly; he was going through my own horrible experience of "drowning on dry land," to quote Garnesk's vigorous phrase. Imagine my astonishment, therefore, when I reached Dennis's side with only a slight difficulty in breathing. There was no sign, or at least very little, of the air which was "heavier than water." Hilderman plunged along behind me, and we reached the stone on which my friend was standing almost simultaneously. Dennis held an arm pointing up the river, his face transfixed with an expression of horrified amazement. Suddenly Hilderman gave a hoarse, shrill shout, breaking almost into a scream.

"Shut your eyes!" he yelled. "Shut your eyes! Oh, for heaven's sake, shut your eyes!"

But I never thought of following his advice. Dennis's immovable arm, pointing like an inanimate signpost up the river, fascinated me. Slowly I raised my eyes in that direction. Then I stepped back with a startled cry, lost my footing, slipped, and fell on my face among the rocks.

The river had disappeared!



CHAPTER XV.

CONCERNS AN ILLUSTRATED PAPER.

The river had disappeared!

In front of us was a great green wall of solid rock, which seemed to tower into the sky above us, and to stretch away for miles to right and left. The curious part about it was that the rock was undoubtedly solid. The shrubs that grew upon it, the great crevices and clefts, were all real. I knew—though I had a hard struggle to make myself believe—that it was all a marvellous and indescribable delusion, for there could be no cliff where only a few seconds before there had been a mighty, rushing torrent.

And yet I could have planted finger and foot on the ledges of that solid precipice and climbed to the invisible summit. Hilderman was muttering to himself beneath his breath, but I was too dazed, my brain was too numbed to make any sense out of the confused mumble of words which came from him. Dennis held my arm in a vice-like grip that stopped the circulation, and almost made me cry out with the pain.

Hilderman staggered, his arm over his eyes, across the stepping-stones to the side of the stream. I found my voice at last.

"Dennis!" I shouted at the top of my voice, though why I should have shouted I can never explain, for my friend was standing just beside me. "Dennis, come away, man. Get out of this!"

I exerted my strength to the uttermost, but Dennis was immovable, rooted to the spot by the strange, snake-like fascination of the nightmare. Then, as suddenly as it had arisen, the rock disappeared again, and there before our startled gaze was a peacefully flowing river. Dennis turned to me with a face as white as a sheet.

"The place is haunted," he said, with a somewhat hysterical laugh.

"Let's get away from it and sit down, and think it over," I urged, pulling him away. We made for the side of the river and sat down, at a very safe distance from the bank. I rolled up my sleeve, and had a look at my arm.

"Great Scott!" Dennis exclaimed, as I dangled the pinched and purple limb painfully. "What on earth did that?"

"I'm afraid it was your own delicate touch and dainty caress that did it, old man. You seized hold of me as if you hadn't seen me for years, and I owed you a thousand pounds."

"Ron, my dear fellow," he said penitently, "I'm most awfully sorry. Why didn't you shout?"

I burst out laughing.

"I entered a protest in vigorous terms, but you were otherwise engaged at the moment, and, anyway, don't look so scared about it, old man; it'll be quite all right in a minute."

Poor Dennis was quite upset at the evidence I bore of his absorption in the miracle, and we postponed our discussion while he massaged the injured arm in order to restore the flow of blood.

"Where's Hilderman?" I asked presently, and though we looked everywhere for the American he was nowhere to be seen.

"He didn't look the sort to funk like that," said Dennis thoughtfully.

"I should have been prepared to bet he was quite brave," I concurred. "Well, anyway," I added, "the main point is, what do you think of our entertainment? You've come a long way for it, but I hope you are not disappointed now you've seen it. It's original, isn't it?"

"By heaven, Ron!" he cried, "you're right. It is original. It is even a more unholy, indescribable mystery than I expected, and I never accused you of exaggerating it, even in my own mind."

"I'm glad that both you and Hilderman have had ocular demonstration of it," I remarked. "It is so much more convincing, and will help you to go into the matter without any feeling that we are out on a hare-brained shadow-chase."

"We're certainly not that, anyhow," Dennis agreed emphatically. "It is a real mystery, Ronald, my boy. A real danger, as well, I'm afraid. But we'll stick at it till the end."

"Thanks, old fellow," I said simply, and then I added, "I wonder what can have become of Hilderman?"

"Gad!" cried Dennis, in sudden alarm. "He can't have fallen into the river by any chance?"

We jumped to our feet and looked about us.

"No," I said presently, "he hasn't fallen into the river." And I pointed a finger out to sea. The Baltimore II., churning a frantic way across to Glasnabinnie, seemed to divide the intervening water in one great white slash.

"I wonder," said Dennis quietly, "is that funk, or isn't it?"

We watched the diminishing craft for a minute or two in silence, and finally decided to keep an open mind on the subject until we might have an opportunity to see Hilderman and hear his own explanation.

"Talking about explanations, what about the left-handed schoolmaster with the red-headed wife, or whatever it was?" I asked.

"That was a bit of luck," said Dennis modestly, "and I will admit, if you like, that we owe that to Garnesk."

"Garnesk wasn't there," I protested.

"No," my friend admitted, "he wasn't there at the time, but he put me on the look-out for a left-handed sailor. I was very much impressed with his deductions about the man who stole Miss McLeod's dog, and I determined to be on the look-out for a left-handed man. I also admit that I carefully watched everyone we met, especially the fishermen at Mallaig, to see if I could detect the sort of man I wanted. I was rewarded when we were pulled out to the Fiona by those two men of Fuller's. One of them was red-headed, you remember? Well, that man was left-handed. It was very easy to observe that by the way he held his oar and generally handled things. Of course I was very bucked about it, so I paid very close attention to him. He wore a wedding-ring—ergo, he was married. It is not conclusive, of course, but a fairly safe guess when you're playing at toy detectives. So when I found the knife I looked for some sign that it belonged to him, and found it. It was all quite simple."

"I daresay it will be when you explain it, but you haven't in the least explained it yet," I pointed out. "How about the schoolmaster and all that, and what made you think the knife belonged to him."

"Simply because he was very probably—working on the law of averages—the only left-handed man among the crew, and that knife belonged to a left-handed man."

"But my dear old fellow," I cried, "you don't seriously mean to tell me that you can say whether a man is left-handed or not by looking at marks on the handle of his knife?"

"Not on the handle," Dennis explained; "on the blade. Have you got a knife on you?"

I produced my pen-knife.

"I'll trust you with it," I declared confidently. "I've never held any secrets from you, Den."

Dennis opened the knife and laid it in the palm of his hand. I stood still and watched him.

"You've sharpened pencils with this knife and the pencils have left their mark. If you hold the knife as you would when sharpening a pencil and look down on the blade there are no pencil marks visible. Now turn the knife over and you will find the marks on the other side of the blade."

"Half a minute," I said eagerly, "let's have a look. The knife is in position for sharpening a pencil and the back of the knife is pointing to my chest. The marks are underneath." I took a pencil from my pocket and tried it. "Yes, I've got you, Dennis. It's quite clear. If I held the knife with the point to my right instead of to my left, as I should do in sharpening with my left hand, the marks appear on the other side of the blade. It is not quite conclusive, Den, but it's jolly cute."

"Not when you're looking for it," he said. "I was struck by the fact that the knife which, by its size and weight, was a seaman's handy tool, had also been used for the repeated sharpening of a blue pencil. When I saw those indications I went through the motion and came to the conclusion that the marks were on the wrong side. Then I tried with my left hand and accounted for it. The blue pencil made me suspicious. I have no knowledge of a yacht-hand's duties, but surely sharpening blue pencils is not one of them. Then the knife had also been carried in the same pocket as a piece of white chalk. The only sort of person I could think of who would carry a piece of chalk loose in his pocket and use a blue pencil continuously was a schoolmaster. So I stated definitely—there's nothing like bluff—that the knife belonged to the left-handed man, who quite obviously had red hair, who appeared to wear the insignia of the married state, and who—again according to the law of averages—had at least one child. I naturally slumped the schoolmaster idea in with it, and there you have the whole thing in a nutshell. But it was Garnesk who set me looking for left-handed clues, and if I hadn't been looking for it, it would never have entered my head."

"But look here," I suggested, "some people sharpen pencils by pointing the pencil to them. Wouldn't that produce the same effect?"

"Yes," he admitted, "I thought of that. But the marks would have been very much fainter, because there would have been much less pressure. I put that idea aside."

"Good!" I exclaimed. "I should much prefer to swallow your theory whole, Dennis, but it struck me that might be a possible source of error, which, of course, might have led us on to a false trail. And, I say, those questions you asked about the time he stayed in port and the hotel. Were those all bluff? Or had you some sort of idea at the back of them?"

"I had a very definite idea at the back of them," Dennis replied. "I thought perhaps the white chalk which was deposited in the blade-pocket, and was even noticeable on the handle, might be due to billiard chalk. But, of course, I didn't mention billiards, because it would have given my line of reasoning away. I thought it was better to spring it on them with a bump."

"Which you certainly did," I laughed. "As a matter of fact, I thought you were simply having a game with us all. But now that you've told me the details, Den, do you remember what happened when you did spring it on them?"

"Well, of course I do," he replied. "But even so, I hardly know what to make of it. I should like to feel confidently that Fuller is the man we are after. But we must remember that both he and Hilderman might very easily have thought I really had discovered something from the knife and been exceedingly surprised without having any guilty connection with the discovery."

"H'm," I muttered, "I prefer to suspect Fuller."

"Oh, I do too," Dennis agreed. "It is safer to suspect everybody in a case like this. But why are you so emphatic?"

"Well," I explained, "we have a few little things to go on. Myra diagnosed that Sholto was taken on a yacht by Garnesk's left-handed man in sea-boots. Then you produce a left-handed member of a yacht's crew out of an old pocket-knife, and Fuller jumps out of his skin when you mention it. That seems to be something to go on, and then there was that incident in the smoking-room."

"When you were reading the paper?" he asked. "I couldn't make that out. Did you notice anything suspicious about it?"

"Of course I was in a suspicious mood," I admitted, "but it struck me as a singularly rude thing to do to snatch the paper out of my hand like that. His remark about Hilderman's precious view was very weak. I think there was something behind it."

"What?" asked Dennis.

"It may have been that there was a letter, or something in the way of a paper, which he didn't want me to see laid inside the paper; but there was another curious point about it. There was a page torn out. I had just noticed this and was on the point of making some silly remark about it when Fuller leaned right across you and took the thing from me, as you saw."

"If the page he didn't want you to see was torn out, there was no chance of your seeing it," Dennis argued, logically enough.

"No," I agreed, "but after your exhibition, if he had anything to conceal he may have been afraid of my even seeing that the page was torn out."

"What do you imagine the missing page can possibly have contained?"

"I don't know," I answered, and thought hard for a minute. "By Jove, Den!" I cried suddenly, "I believe I've got it. This takes us back to Garnesk's idea of a wireless invention causing all the trouble. We think we have reason to believe that Fuller may have stolen the dog. We also think we have reason to believe that one of his yacht-hands is what you called 'a mathematical master.' Now, suppose the paper had got hold of this and printed an illustration of the mysterious invention or perhaps a photograph of the mysterious inventor?"

"And the inventor, knowing that we should accuse him of blinding Miss McLeod and making off with her dog, the moment we could identify him, tears out the offending illustration in case either we or anyone else in the neighbourhood should see it? He admitted, by the way, that he never went into port if he could help it."

"Well, anyway," I said, "we'll have a look for the paper and find the missing page."

"You noticed the date?" Dennis asked, anxiously.

"Oh! it was this week's issue," I replied.

"Do they take it at the house?" he inquired, again with a note of anxiety.

"Not that I know of, but we'll rake one up somewhere, don't you fret. And, I say, this is a fine way to welcome a visitor; you haven't even said how-do to your host and hostess. I'm most awfully sorry."

"Don't be an ass, Ronnie," said Dennis, cheerfully. "With the utmost respect, as you barrister chaps would say, I hadn't noticed your departure from the requirements of conventional hospitality. I wouldn't have missed this for all the world and a bit of Bond Street."

So then we hurried to the house with a nervous energy, which spoke eloquently to our state of suppressed excitement.

"All the same," Den muttered dolefully, as we hurried down the stable path, "it's going to be what the Americans would call 'some' wireless invention that can plant a grown-up mountain in the middle of an innocent river in the twinkling of an eyelash."

"It is, indeed, old fellow," I agreed, "but don't let us worry about that. We'll get in and see Myra and the General, and then have a look round for the Pictures—the paper you were looking at."

We found Myra sitting on the verandah and wondering what on earth had kept us, and if we had changed our minds and gone straight back south with Garnesk.

"I'm most awfully sorry, darling," I apologised. "It's all my fault, of course. We went to Glasnabinnie, and since then I've been showing Dennis the river and generally forgetting my duties as deputy host."

"What did you go to the river for?" Myra asked, suspiciously.

"Oh! just to have a look round, you know, dear. It's a very nice river," I replied, airily.

"Ronnie, dear, please," she said gently, laying her hand on my arm and turning her veiled and shaded face to mine, "please don't joke about it. I can't bear to think of you running risks there."

I looked at my beautiful, blind darling, and a pang shot through me.

"God knows I'm not joking about it, dearest," I said sadly.

"I know you weren't really, Ronnie. But, please, oh! please, keep away from the river."

"Very well, dear," I promised, "I will, unless an urgent duty takes me there. We must solve this mystery somehow, and it may mean my going to the river. But I promise not to run any unnecessary risks."

"I'll keep an eye on him and see that he takes care of himself, Miss McLeod," said Dennis, coming to the rescue.

"Thank you, Mr. Burnham," the girl replied, "but you know it applies to you as well. You must look after yourself also."

"By the way, dear," I asked, changing the subject, "have you a copy of this week's Pictures?"

"I'm afraid not," she answered. "Must it be the Pictures? I've just been looking at another illustrated paper."

"Looking at what?" I cried, jumping to my feet. "Darling, who's talking about running risks?"

"Oh, it's all right, dear," she assured me. "I got Mary to bring my dark-room lamp down to the den and just glanced at the pictures by the red light. But I won't do it again, if it alarms you, dear. All the same, I'm quite sure I could see by daylight."

"You promised Garnesk you wouldn't till you heard from him, darling," I urged. "It might be very dangerous, so please don't for my sake."

"Very well, then," Myra sighed, "I'll try to be good. But I hope he'll write soon."

"Where do you think we could get a copy of the paper?" I asked shortly.

"If it's frightfully important, dear, you might get one in Glenelg, and, failing that, Doctor Whitehouse would lend you his. I know he takes it in. Why are you so keen about it?"

"We'll go into the den and tell you everything in a minute or two, dear," I promised. "Is there any objection to my sending Angus in to the doctor?"

"None whatever," Myra declared, "he can go now if you like."

So after I had despatched Angus into the village with strict instructions not to come back without a copy of the paper if he valued his life, we all adjourned to Myra's den, and my friend and I told her in detail everything that had happened. About an hour and a half later Angus returned with the paper. I took it from him with a hurried word of thanks and nervously turned over the pages.

"Ah! here's a page I didn't see," I exclaimed excitedly, but the only thing on the whole page was a photograph of a new dancer appearing in London. Without waiting for me to do so, Dennis leaned over me and turned the page over with a quick jerk of the wrist.

"Phew!" I exclaimed involuntarily, and Dennis gave a long, low whistle.

"Oh! what is it? Tell me!" pleaded Myra, anxiously.

"It's a photograph of our friend Fuller," I replied slowly, in a voice that shook with excitement. "And he's wearing court dress, and underneath the photograph are the words 'Baron Hugo von Guernstein, Secretary of the Military Intelligence Department of the Imperial German General Staff.'"



CHAPTER XVI.

DISCLOSES CERTAIN FACTS.

"There's no doubt about it," I remarked as soon as we had partially recovered from our surprise. "That's Fuller right enough."

"Oh! there's no doubt it's our man," said Dennis emphatically. "Even if we had not the evidence of the torn page to corroborate it, the likeness is perfect."

"Yes," I agreed, "but what do you think his game can be? I'm coming round to Garnesk's wireless theory."

"Whatever it is, we've stumbled on something of real importance this time. We must find out what it is and show it up at once."

"I hope you'll take care," said Myra anxiously. "I shouldn't mind so much if I could be with you to help, but it's dreadful to sit here and know you are in danger and not be able to do anything at all."

"I'm very glad you can't, darling," I said heartily, as I threw my arm round her shoulders. "I don't want you to come rushing into these dangers, whatever they may be. In a way I am glad you are not able to join us, because I know how difficult it would be to stop you if you were."

"I suppose this is all one affair," she said doubtfully. "You don't think this is something quite different from the green ray? It might be two quite separate things, you know."

"I don't think we are likely to meet with two such interesting problems in such a remote locality unless they are connected with each other, Miss McLeod, and especially as everything else apart from the photograph of Baron von Guernstein points to Fuller as the culprit. I think we can take it that in solving one mystery we provide the solution to the other."

"I quite agree with you, Dennis," I said, "but what I am worrying about now is, what we are going to do."

"The first thing you must do is to dress for dinner, and not let anyone imagine there is anything untoward about," Myra advised. "And please don't tell father you have been lunching with one of the Kaiser's principal spies, if that's what the Baron's title really means. I would much rather you said nothing to him at all about it for the present, and in any case you must have something definite in mind as to your plans before you put the matter to him. If you tell him you don't know what to do about it he will be in a dreadful state. He is very far from well, and all this business has told on him dreadfully."

"That is very excellent advice, Miss McLeod," Dennis agreed warmly. "Ronald, we'll go and disguise ourselves as ordinary, undisturbed human beings and hide our fears and doubts behind the breastplate of a starched shirt. Come along."

So Dennis dragged me away, and then, realising his indiscretion, allowed me to return to my fiancee "just for two minutes, old fellow."

Dinner was a curious meal, though not quite so strange as the meal the General and I had together the night, less than a week before, that Myra lost her sight.

I hope I shall never live through a week like that again. Even now, as I look back, I cannot believe that it all happened in seven days. It still seems to have been something like seven months at the very least.

We had one thing in our favour as we sat down to the table; we all had a common object in view. We were each of us determined to forget the green ray for a moment. Fortunately the old man took an immediate fancy to Dennis and that brightened me considerably. There are few things so pleasant as to see those whose opinion you value getting on with your friends. Only once, and that after Mary McNiven had come to take poor Myra away, did the subject of the green ray crop up.

"Mr. Burnham knows about it all, I suppose?" the General asked.

"I've told him everything, and Garnesk and I went over the whole thing with him before the train went."

"Good!" said the old man emphatically. "Excellent fellow Garnesk—excellent; in fact, I don't know when I've met such a thundering good chap. No new developments, I suppose?"

I hesitated. I could not have brought myself to lie to him, and in view of the startling complications with which we had so recently been confronted, I was at a loss for an answer. Dennis came to my rescue just in time.

"I think Ron's difficulty is in defining the word 'developments,' General," said he. "If we said there were developments it would naturally convey the impression that we had something definite to report. I think perhaps the best way to put it would be that we believe we are getting on the right scent, by the simple process of putting two and two together and making them four. We hope to have something very decided to tell you in a day or two."

"I shall be glad to hear something, I can assure you," said the old man, "but in the meantime we will try to forget about it. You have had a tiring journey, Mr. Burnham, followed by a strange initiation into what is probably a new sphere of life altogether—the sphere of mysteries and detectives, and so forth. No, Ronald, we'll give Mr. Burnham a rest for to-night."

But just as I was congratulating myself that we had escaped from the painful necessity of putting him off with an evasive answer, if not a deliberate lie, the butler entered and announced that he had shown Mr. Hilderman into the library.

"Well, as we are ready, we had better join him," said the old man, and we adjourned to the other room.

Now if Hilderman should by any tactless remark betray our strange experience in the afternoon there would be the devil to pay. I followed the General into the library, beckoning to the American with a warning finger on my lip. He saw at once what I meant, fortunately, and held his tongue, and we all talked of general matters for some little time. Then Hilderman took the bull by the horns.

"As a matter of fact, General," he announced boldly, "I ran over to have a word with Mr. Ewart about a certain matter which is interesting us all. I don't suppose you wish me to worry you with details at the moment?"

"I should be very glad to hear what you have to tell us, Mr. Hilderman, but unfortunately I—er—I have a few letters I simply must write, so I hope you will excuse me. My daughter is in the drawing-room, so perhaps you fellows would care to join her there. Her counsel will be of more use to you than mine in your deliberations, I have no doubt."

However, when we looked for her in the drawing-room Myra was not there, and I found her in her den.

"Why not bring him in here?" she asked. "He won't bite, and it will be more conducive to a free and easy discussion. I should like to hear what he has to say for himself in view of his running away this afternoon, and I shouldn't feel comfortable in the drawing-room with this shade on. In here I feel that he must just put up with any curiosities he meets."

So we made ourselves comfortable in the den, and Hilderman sat in a chair by the window.

"Of course, you know what I have come to speak about, Mr. Ewart," he began at once. "You must have thought my conduct this afternoon was very strange—very unsportsmanlike, to say the least."

"Oh, I don't know," I replied as lightly as I could. "It was a very strange affair, and it rather called for strange conduct of one sort or another."

"Still, you must have thought it cowardly to run away as quickly as I could," he insisted.

"It was some time before we even noticed you had left us," I laughed, "and then, I confess, I couldn't quite make out where you had got to or why you had gone."

"As a matter of fact we were rather scared," Dennis put in. "We searched for you in the river."

"It sounds a very cowardly confession to make," Hilderman admitted, "but I went back to the landing-stage, got into my boat, and cleared off as quickly as I could. I must ask you to believe that I was under the impression that it would be best for us all that I should. But my idea proved to be a bad one and nothing came of it. So here I am to ask you if you have learned anything or have anything to suggest."

"I'm afraid we're more at a loss than ever now," I admitted. "The further we get with this thing the less we seem to know about it, unfortunately."

Hilderman was exceedingly sympathetic, and though he made numerous suggestions he was as puzzled as we were ourselves. I had some difficulty in defining his attitude. We knew as much as was sufficient to hang his friend "Fuller," but I could not make up my mind whether he really was a friend of von Guernstein's or not. It was a small thing that decided me. On an occasionable table beside the American lay a steel paper-knife, a Japanese affair, with a carved handle and a very sharp blade. Hilderman picked up the knife and toyed with it.

"I should be careful with that, Mr. Hilderman," I advised. "That is a wolf in sheep's clothing; it's exceedingly sharp."

"Oh, yes!" cried Myra. "If you mean my paper-knife, it ought not really to be used as a paper-knife at all, the point is like a needle. I must put it away or hang it up as an ornament."

The American laughed and laid the knife down again on the table, and we resumed our discussion. Both Dennis and I knew that we must be very careful to conceal our suspicions, but at the same time we did our best to reach some sort of conclusion with regard to Hilderman himself.

"And, I suppose, until you have searched about the Saddle," he remarked, "you will be no further on as to who stole Miss McLeod's dog. It seems to me that the dog was taken by the man who wished to conceal an illicit still, and the green flash, or green ray, or whatever you call it, is simply a manifestation of some strange electrical combination in the air."

"I'm afraid we shall have to leave it at that," I said with an elaborate sigh of regret.

"Not when you have Mr. Burnham's distinguished powers of deduction to assist you, surely, Mr. Ewart?" said Hilderman, and waited for an answer.

"Flukes are not very consistent things, I fear," Dennis supplied him readily, "and if we are to make any progress we shall hardly have time for idle speculation."

"Fortune might continue to favour you," the American persisted. "Don't you think it's worth trying?"

"I'm afraid not," said Dennis, with a laugh that added emphasis and conviction to his statement.

"By the way," Myra suggested, "I don't know if anybody would care for a whisky and soda or anything. I won't have drinks served in here, but if anybody would like one, you know where everything is, Ron. I always say if anyone wants a drink in my den they can go and get it, and then I know they really like being in the den. You see I'm a woman, Mr. Hilderman," she laughed.

"I must say I think the idea of refreshment would not enter the head of anyone who had the pleasure of your company here, Miss McLeod, unless you suggested it yourself."

We laughed at the rather heavy compliment, and I went into the dining-room to fetch the decanters, syphons and glasses.

"I'll help you to get them," called Dennis, and followed me out of the room.

"Well?" I asked as soon as we reached the other room. "What do you make of it?"

"I'm not sure," Dennis admitted. "I'm puzzled. I shouldn't be surprised if he turned out to be a Government secret service man keeping an eye on Fuller-von-Guernstein, and that when he has quite made up his mind that the mystery of the green ray is connected with his own business he will show his hand."

"Something of the same sort occurred to Garnesk," I said. "Well, at present we'd better avoid suspicion and go back before he thinks we're holding a committee meeting."

So I led the way to the den. I was walking carefully and slowly, because I was unaccustomed to carrying trays of glasses and things, and consequently I made no noise. I pushed the door open with my shoulder, Dennis following with a couple of syphons, and as I did so I chanced to glance upwards.

In a large mirror which hung over the fireplace I saw the reflection of Hilderman's face, knitted in a fierce frown, gazing intently at some object which was outside my view. Myra was talking, though what she was saying I did not notice. I went into the room and put the tray on the big table, and as I filled the glasses I looked round casually to see what Hilderman had been looking at. Lying on the sofa on which Myra was sitting was the copy of the Pictures, open at the page bearing the incriminating photograph!

I mixed Hilderman's drink according to his instructions—for by this time he had entirely recovered his equanimity—and handed it to him. As I did so I happened to look in the direction of the small table beside him. Myra's Japanese paper-knife was still there, but the point had been stuck more than an inch into the mahogany top of the table. I turned away quickly, with a laughing remark to Myra, which did not seem to raise any suspicion at the time, though I have no recollection now what it was I said.

A few moments afterwards I quietly and unostentatiously slipped out of the room. Surely there could be no doubt about it now. The whole thing was obvious. Hilderman had noticed the paper, jumped to the conclusion that we suspected everything, and in the sudden access of baffled rage had picked up the paper-knife and stabbed it into the table.

There was only one possible reason for that—Hilderman was an enemy. In that case, I thought, he has come here to try and find out how much we know and to keep an eye on us. Possibly he might be attempting to keep us there so that Fuller could get up to some satanic trick elsewhere. I decided to act at once. I turned back to the den and put my head round the door.

"Will you people excuse me for a bit?" I said lightly. "The General wants me." And with that I left them. I had almost asked Hilderman not to go till I came back, but I was afraid it might sound suspicious to his acute ears. I hardly knew what to do. I should have liked to have been able to speak with Dennis, if only for a moment. Indeed, I am quite ready to confess that just then I would have given all I possessed for ten minutes' conversation with my friend. I stole quietly out of the house, and thought furiously.

If Hilderman wanted to keep us from spying on Fuller, where was Fuller? Would I be wiser to wait and try to keep an eye on Hilderman, or was my best plan to ignore him and try and locate his German friend? I decided on the latter course. I went back and wrote a short note to Dennis and slipped it inside his cap.

"I'm convinced they are both enemies. Take care of Myra. I may be out all night. Don't let her worry about me; I may not be back for some time, but I shall come back all right.—R."

I left this for my friend, knowing that sooner or later he would find it, and went down to the landing-stage. The Baltimore II. and Myra's boat, the Jenny Spinner, were drawn up alongside, and I realised that if I took the Jenny I should be raising Hilderman's suspicions at once. Anchored a little way out was another small motor-boat—the first the General had—which Myra had also called after a trout fly—the Coch-a-Bondhu—though the play upon words was lost on most people. The boat was still in constant use, and Angus and Hamish continually went into Mallaig and Glenelg in it to collect parcels and so on. I ran to the petrol shed, and got three tins of Shell, put them in the dinghy and pushed out to the Bondhu, climbed on board, sounded the tank, filled it up, and started out across the Loch. I can only plead my anxiety to get well out of sight and hearing before Hilderman should think of leaving the house, as an excuse for my lamentable thoughtlessness on this occasion. Indeed, it was not till long afterwards that I realised I had forgotten to anchor the dinghy, and I left it, just as it was, to drift out to sea on the tide.

I made all the pace I could and reached the other side in about twenty minutes. I was sadly equipped for an adventurous expedition! I had no flask to sustain me in case of need, no weapon in case I should be called to defend myself; I was wearing a dinner-jacket, no hat, and a pair of thin patent-leather pumps!

I ran the boat right in shore, heedless of the danger to the propeller, in a small sandy cove round the point, so that I was hidden from Glasnabinnie. Then I realised that I had been a little too precipitate in my departure. There was no anchor-chain on board, and the painter was admirably suited for making fast to pier-heads and landing-stages at high tide, but was nothing like long enough to enable me to make the craft secure on short. However, I dragged her as far up as I could, and prayed that I might be able to return before the tide caught her up and carried her away. In those circumstances I should have been stranded in the enemy's country, by no means a pleasing prospect!

Having done the best I could for Myra's faithful motor-boat, I made my way round the hill, climbing cautiously upwards all the time, my dinner-jacket carefully buttoned in case a gleam of moonlight on my shirt-front should give me away at a critical moment. It was a rocky and difficult climb, and I soon regretted that I had not taken the bridle path to Glasnabinnie and made my way boldly up the bed of the burn. However, it was too late to turn back, and eventually, after one or two false steps and stumbles, I succeeded in reaching a spot from which I could obtain a good view of the hut. No, there was no light there, no sign of movement at all. I decided to work my way round to the other side and then, if I continued to get no satisfaction, to descend to the house. The windows of the hut, or smoking-room, as the reader will no doubt remember, extended the whole length of the structure; and surely, I thought, if there were a light in the place it would be bound to be visible. I edged round the face of a steep crag, floundered across the stream between the two falls, getting myself soaked above the knees as I did so, and crouched among the heather on the other side of the building. No, there was no one there, the place was deserted. I knelt down and peered about me listening intently.

Not a sound greeted my expectant ear save the incessant rumble of the falls. Then as I turned my attention to the house itself and looked down the course of the burn to Glasnabinnie, I could scarcely suppress a cry of astonishment. For there below me, moving to and fro between the house and the hut, was a constant procession of small lights, like a slowly moving stream of glow-worms, twenty or thirty yards apart. I was rooted to the spot. What could it mean? Was this another weird natural manifestation, or was it, as was much more likely, a couple of dozen men bearing lights? Yes, that was it, men bearing lights—and what else besides? Men don't climb up and down steep watercourses in the night for the sake of giving an impromptu firework display to an unexpected visitor, I told myself. There was only one thing to do, and that was to investigate the matter and chance what might happen to me. I crept down to the hut, and lay on my face among the heather and listened. Here and there a mumble of voices, now and then a subdued shout, apparently an order to be carried out by the mysterious light-bearers, broken occasionally by the shrill call of a gull, conveyed nothing to me that I could not see. I looked up at the hut. No, there was no one there, and the windows were not screened, because I could see the moonlight streaming through the far side. Yet, surely, the hut must be their objective, I thought. Where else could they be going to? Fascinated, I crawled on my hands and knees till I could touch the walls of the smoking-room by putting out my arm. I heard a great commotion coming, it seemed, from the very ground beneath my feet.

I laid my ear to the ground and listened. The noise grew louder, and the voices seemed to be shouting against a more powerful sound—the waterfall, possibly. I thought perhaps the floor of the hut would give me more opportunity to locate the source of the disturbance. I threw caution to the winds and slipped through the wide windows into the room. I moved as carefully as I could, however, once my feet found the floor, for if there should be anyone below they would probably hear me up above. I turned back the carpet in order to hear more distinctly, and as I did so I noticed a rectangular shaft of light which trickled through the floor. There was a trap-door. I knelt down and lifted it cautiously by a leather tab which was attached to one side of it and peered through. I can never understand how it was I did not drop that hatch again with a self-confessing crash when I realised the extraordinary nature of the sight that greeted my eyes. There was I in the smoking-hut of a peaceful American citizen, where only a few hours before I had spent a pleasant hour in friendly conversation, and now I was lying on the edge of the entrance to a great cavern.

Below me there was a confused mass of machinery and men. Some were working on scaffolding, others were many feet below. The nearest of them was so close to me that I could have leaned down and laid my hand on his head. I tried to make out what they were doing, but except that they were dismantling the machinery, whatever it might be, I could make nothing of it. I watched them breathlessly, trembling lest at any moment one of them should look up and detect my presence.

The place was lighted by electricity, though there were not enough lamps to illuminate the cavern very brightly, and as my eyes got accustomed to the lights and shadows I was able to make out the cause of this.

Evidently there was a turbine engine below, driven by the water from the falls, which supplied the necessary power. After a moment or two it dawned on me how the cavern came to be there; it was, or had been, the course of a hidden river, such as are common enough among the mountains, but the stream had been diverted, probably by some sort of landslide, and had left this tumbler-shaped cave, resembling a pit shaft. Now, I thought, I have only to find out what all this machinery is for and the whole mystery is solved. I opened the trap a little further, and allowed my body to hang slightly over the edge.

Then for the first time I saw, to my right, fixed so that it almost touched the floor of the hut, a great round brass object, mounted on an enormous tripod, which, again, stood on a platform. In front of this was a large square thing like a mammoth rectangular condenser, such as is used for photographic enlarging and other projection purposes. Had it not been for this condenser I should have taken the whole thing to be an elaborate searchlight. But, I asked myself, what would be the good of a searchlight there? Suddenly the whole truth dawned upon me.

The searchlight must operate through a trap in the wall of the hut just below the floor. I leaned further in, forgetting my danger in the intoxication of sudden discovery.

Only a foot or two away from me a man was working on the searchlight. Carefully taking it to pieces, he was handing the parts to another man, who was perched on the scaffold below him. He was so close to me that I could hear him breathing. I was about to wriggle back to safety when he looked up. He gave a sudden loud shout. I lay there fascinated. After all, I thought, before they can reach me I can slip out and edge round the cliff, run down on to the shore, and get away in the motor-boat. But I had reckoned without my host. Even as the man shouted, and the others left their work to see what was the matter, Fuller dashed out from behind the platform, gave one terrified look at me, and, flinging himself at the wall of the cavern, threw all his weight on a rope which dangled there. I scuttled to my feet, intending to make a bolt for it. But the boards shivered beneath me, and, before I could realise what was happening, I found myself hurtling through the air to the floor of the cavern below.



CHAPTER XVII.

SOME GRAVE FEARS.

And now, as the reader will readily understand, I must continue the story as it was afterwards related to me.

Myra, the General, and Dennis sat up and waited for me till the early hours of the morning, but I did not return. The young people did what they could to assure the old man that my sudden and unexpected disappearance had been entirely voluntary, and Dennis, who had found my note, as soon as he put on his cap to stroll out casually, and see where I had got to, gave him subtly to understand that it was really part of a prearranged plan, and Myra at length persuaded him to go to bed at midnight.

When I failed to put in an appearance at breakfast-time, however, even they began to be a trifle alarmed, but they did their best to conceal their fears. They scoured the hillside and then went down to the landing-stage. Dennis had reported the previous night that the motor-boat was still in its place when he saw Hilderman off, and it never occurred to Myra that I might make my departure in the Coch-a-Bondhu.

"He hasn't gone by the sea, any way," Dennis announced again, as he and the girl stood on the landing-stage.