Our next step in the inquiry was a domiciliary visit to Beacon House.

While the public, including Mr. Day, were expecting to see his nephew, we, of course, were hoping to find old Gregory.

In this we were disappointed. Already Treeton knew that both men were missing from their lodgings. Yet while the police were watching everywhere for the dandified young man from London, the queer, white-haired old Sheffield steel manufacturer had slipped through their fingers and vanished as though the earth had swallowed him up.

Mrs. Dean's house was a typical seaside lodging-house, plainly and comfortably furnished—a double-fronted house painted pale blue, with large airy rooms and bay windows, which, situated high up and on the very edge of the cliff, commanded extensive views up and down the coast.

The sitting-room occupied by uncle and nephew, proved to be a big apartment on the first-floor, to the left of the entrance. The houses in that row had a front door from the asphalt path along the edge of the cliff and also a back entrance abutting upon the narrow street which ran into the centre of the town. Therefore, the hall went from back to front, the staircase ascending in the centre.

The room in which I stood with the detectives, was large, with a cheerful lattice-work wall-paper, and substantial leather-covered furniture. In the window was placed a writing-table, and upon it a telescope mounted on a stand. A comfortable couch was placed against the wall, while before the fire-place were a couple of deep-seated easy chairs, and a large oval table in the centre.

Indeed, the room possessed an air of homely comfort, with an absence of the inartistic seldom found in seaside apartments. The windows were open and the light breeze from the sun-lit sea slowly fanned the lace curtains. On the writing-table lay a quantity of papers, mostly tradesmen's receipts—all of which the old gentleman carefully preserved—some newspapers, a tin of tobacco, and several pipes.

Beside the fire-place lay a pair of Egyptian slippers in crimson morocco, evidently the property of young Craig, while his straw hat and cane lay upon the couch, together with the fawn Burberry coat which had been one of the common objects in Cromer. Everywhere were signs of occupation. Indeed, the cushions in the easy chairs were crumpled just as if the two men had only a little while before arisen from them, while in the grate were a number of ends of those gold-tipped cigarettes without which Craig was never seen.

Upon a peg behind the door hung another old grey mackintosh belonging to old Gregory—an exact replica of which had been worn by the man who had so mysteriously met his death.

But where was old Gregory? Aye, that was the question.

With Mrs. Dean, a homely person with hair brushed tightly back, and her husband looking on, we began a thorough search of the room, as well as of the two bedrooms on the next floor. The sitting-room was investigated first of all, but in the writing-table we found nothing of interest. One of the drawers had been emptied and a mass of tinder in the grate told a significant tale.

Old Mr. Gregory had burned a lot of documents before disappearing.

Why? Were they incriminating?

Why, too, had he so suddenly disappeared? Surely he would not have done so without knowledge of his nephew's tragic death!

For a full half-hour we rummaged that room and all that was in it, but, alas, found nothing.

In the old man's bedroom stood a battered leathern cabin-trunk bearing many labels of Continental hotels. It was unlocked, and we found it filled with clothes, but strangely enough, not the clothes of an old man, but rather the smart attire of a middle-aged person of fashion.

At first Frayne refused to believe that the trunk belonged to old Gregory. But Mrs. Dean was precise upon the point. That was Mr. Gregory's room.

In the bottom of the cabin-trunk we found a number of folded sheets of foolscap, upon which were written many cryptic calculations in feet and metres; "wave-metres," it was written upon one slip. They seemed to be electrical. Upon other sheets were lists of names together with certain figures, all of which conveyed to us no meaning. Frayne, of course, took possession of them for submission to examination later on.

"May I look at them later?" I asked him.

"Certainly, Mr. Vidal. They seem to be a bit of a puzzle, don't they? They have something to do with electricity, I fancy."

In the corner of the room, opposite the window, stood a large wooden sea-chest, similar to those used by naval officers. It was painted black, and bore, in white, the initials "V. G." It had an old and battered appearance, and the many labels upon it told of years of transit by rail and steamer.

I bent to examine it, but found it securely locked and bound round with iron bands.

"That's very heavy, sir," Mrs. Dean remarked. "He always kept it locked, so I don't know what's inside. When the old gentleman came in, he always went straight over to it as though to ascertain whether the lock had been tampered with."

"Ah, then there's something in there he wished to keep away from prying eyes!" said Frayne. "We must see what it is."

I remarked that the lock was a patent one, but he at once ordered a locksmith to be fetched, while we turned our attention to the adjoining room, the one that had been occupied by young Craig.

It was slightly smaller than the other one, and overlooked the narrow street which ran along the back of the houses towards the church.

We searched the drawers carefully, one after another, but found nothing except clothes—a rather extensive wardrobe. Of cravats, Craig had possessed fully a hundred, and of collars, dozens upon dozens.

Upon his dressing-table stood the heavy silver fittings of a travelling-bag, a very handsome set, and, in a little silver box, we found a set of diamond studs, with several valuable scarf-pins. The device of one of these was some intertwined initials, surmounted by a royal crown in diamonds; apparently a present from some exalted personage.

Presently, however, Treeton, who had remained in Gregory's room assisting in the perquisition, entered with an ejaculation of surprise, and we found that on pulling out the small drawer of the washstand, he had discovered beneath it some papers that had been concealed there.

We at once eagerly examined them, and found that there were slips exactly duplicating those discovered in old Gregory's wallet—slips with names and numbers upon them—apparently code numbers.

Together with these were several papers bearing more remarkable calculations, very similar to those we had found at the bottom of the cabin-trunk. The last document we examined was, however, something very different. It was a letter written upon a large sheet of that foreign business paper which is ruled in small squares.

"Hulloa!" Frayne exclaimed, "this is in some foreign language—French or German, I suppose."

"No," I said, glancing over his shoulder. "It's in Italian. I'll read it, shall I?"

"Yes, please, Mr. Vidal," cried the detective, and handed it to me.

It bore no address—only a date—March 17th, and translating it into English, I read as follows:—

"Illustrious Master,—The business we have been so long arranging was most successfully concluded last night. It is in the Matin to-day, a copy of which I send you with our greeting. H. left as arranged. J. arrives back in Algiers to-morrow, and the Nightingale still sings on blithely. I leave by Brindisi for Egypt to-night and will wire my safe arrival. Read the Matin. Does H. know anything, do you think? Greetings from your most devoted servant, Egisto."

"A very funny letter," remarked Treeton. "I wonder to what it alludes?"

"Mention of the Matin newspaper would make it appear that it has been written from Paris," I said. Then, with Frayne's assent, I rapidly scribbled a copy of the letter upon the back of an envelope which I took from my pocket.

A few moments later, the locksmith having arrived, we returned to old Gregory's room, and watched the workman as he used his bunch of skeleton-keys upon the lock of the big sea-chest. For ten minutes or so he worked on unsuccessfully, but presently there was a click, and he lifted the heavy wooden lid, displaying an old brown army blanket, carefully folded, lying within.

This we removed, and then, as our astounded gaze fell upon the contents of the chest, all involuntarily gave vent to loud ejaculations of surprise.

Concealed beneath the rug we saw a quantity of antique ornaments of silver and gold—rare objects of great value—ancient chalices, reliquaries, golden cups studded with precious stones, gold coronets, a great number of fine old watches, and a vast quantity of splendid diamond and ruby jewellery.

The chest was literally crammed with jewels, and gold, and silver—was the storehouse of a magnificent treasure, that must have been worth a fabulous sum.

I assisted Frayne to take out the contents of the chest, until the floor was covered with jewels. In one old brown morocco case that I opened, I found a glorious ruby necklet, with one enormous centre stone of perfect colour—the largest I had ever seen. In another was a wonderful collar of perfectly matched pearls; in a third, a splendid diamond tiara worth several thousand pounds.

"Enough to stock a jeweller's shop," said Frayne in an awed voice. "Why, what's this at the bottom?"

He began to tug at a heavy square wooden box, which, when he had succeeded in dragging it out and we opened it, we found to contain a hand flash-lamp for signalling purposes—one of the most recent and powerful inventions in night-signalling apparatus.

"Ha!" Treeton cried. "That's the lamp which Day suspected had been flashed from these windows on the night of the coast alarm."

"Yes," I remarked reflectively, "I wonder for what purpose that lamp was used?"

"At any rate, the old man has a fine collection of curiosities," said Frayne. "I suppose it was one of his eccentricities to carry them with him? No wonder he was so careful that the lock should not be tampered with!"

I stood looking at that strange collection of valuables. There were pieces of gold and silver plate absolutely unique. I am no connoisseur of antique jewellery, but instinctively I knew that every piece was of enormous value. And it had all been thrown pell-mell into the box, together with some old rags—seemingly once parts of an old damask curtain—in order to prevent the metal rattling. Much of the silver-ware was, of course, blackened, as none of it had been cleaned for years. But the gems sparkled and shone, like liquid drops of parti-coloured fire, as they lay upon the shabby carpet. What could it all mean?

Mrs. Dean, who was standing utterly aghast at this amazing discovery, jumped with nervousness as Frayne suddenly addressed her.

"Did Mr. Gregory have many visitors?"

"Not many, sir," was her reply. "His secretary used to come over from Sheffield sometimes—Mr. Fielder, I think his name was—a tall, thin gentleman, who spoke with an accent as though he were a foreigner. I believe he was a Frenchman, though he had an English name."

"Anybody else?"

"Mr. Clayton, the old schoolmaster from Sheringham, and—oh, yes—a lady came from London one day, a short time ago, to see him—a young French lady," replied Mrs. Dean.

"What was her name?"

"I don't know. It's about a fortnight ago since she came, one morning about eleven, so she must have left London by the newspaper train. She rang, and I answered the bell. She wouldn't let me take her name up to Mr. Gregory, saying: 'She would go up, as she wanted to give him a surprise.' I pointed out his door and she went in. But I don't think the old gentleman exactly welcomed her."

"Why?" I asked.

"Because I heard him raising his voice in anger," replied the landlady.

"Was Mr. Craig there?"

"No. He was out somewhere I think. My own belief is that the young lady was Mr. Gregory's daughter. She stayed about an hour, and once, when I opened the door, I heard her speaking with him very earnestly in French, asking him to do something, it seemed like. But he flatly refused and spoke to her very roughly; and at this she seemed very upset—quite brokenhearted. I watched her leave. Her face was pale, and she looked wretchedly miserable, as though in utter despair. But I forgot," added Mrs. Dean. "Three days later I found her photograph, which the old man, who was very angry, had flung into the waste-paper basket. I kept it, because it was such a pretty face. I'll run down and get it—if you'd like to see it."

"Excellent," exclaimed Frayne, and the good woman descended the stairs.

A few moments later she came back with a cabinet photograph, which she handed to the detective.

I glanced at it over his shoulder.

Then I held my breath, staggered and dumbfounded.

The colour must have left my cheeks, I think, for I was entirely unprepared for such a shock.

But I pulled myself together, bit my lip, and by dint of a great effort managed to remain calm.

Nevertheless, my heart beat quickly as I gazed upon the picture of that pretty face, that most open, innocent countenance, that I knew so well.

Those wide-open, trusting eyes, that sweet smile, those full red lips—ah!

And what was the secret? Aye, what, indeed?