Chapter Seventeen. “The Plot Revealed.”

Within a week the man Tegelmund, accompanied by Engström, arrived in Paris and took up his abode in an obscure hotel near the Gare du Nord. But, though we kept a careful watch upon the pair, Engström, ever elusive and resourceful, suddenly disappeared! For six days he was absent. Then, as suddenly and mysteriously, he appeared again at the hotel.

Aubert, who had been detailed to watch Tegelmund, now reported that the latter had been across to the Orleans goods station, inquiring about some heavy cases of goods which had arrived from Lisbon.

“I have contrived to open one of the cases,” he said. “It contains some complicated and apparently delicate machinery, with a small dynamo. Apparently it is some sort of wireless plant, but, beyond that, I cannot make head or tail of it.”

At Aubert’s suggestion I went late one night to the Orleans goods yard. Aubert, by methods of persuasion not wholly original, had contrived to make friends with one of the officials, and we had no difficulty in securing access to the great goods shed, now silent and deserted, in which the mysterious cases lay. Prising open one end of the topmost case, I inspected the contents as closely as I could with the aid of my pocket flash-lamp. Within was what certainly appeared to be a wireless plant of some kind, but it was of a description entirely new to me, and I could not see enough of it to gain any idea of its purpose. Of course we dared not risk unpacking it. But we had made a great advance. The big cases could not be secretly moved, and our friend, the goods official, undertook to let us know promptly when he received orders to release them.

We waited in patience for a week, but still the cases remained untouched and uncalled for. Then came an incident which threw a flood of light on the proceedings of our enemies, though it told us nothing of their real motive; we were to learn that later.

One day I was strolling aimlessly along the Boulevard des Capucines, when I heard my name pronounced in accents of delighted surprise. Turning round, I instantly recognised an old friend in the person of Captain A—, who was one of the experts attached to the submarine branch of the British Admiralty.

“My dear Sant,” he exclaimed joyfully. “Who would have thought of meeting you here? I am alone in Paris. I know no one and am bored to death. What have you got on hand now? I thought you were in New York.”

“I certainly didn’t expect to meet you here,” I replied. “What has brought you over?”

“Come and have some lunch, and I’ll tell you all about it,” he replied, and we repaired to an adjoining café, where Captain A— promptly ordered lunch in a private room.

“We’ve got a new thing on hand in the submarine line,” he told me as soon as the waiter had left the room. “You know we have been trying some experiments in German waters lately, and the Hun destroyers have been so confoundedly active that our fellows have had to pass a lot of their time sitting on the bottom. As a consequence, some of the crew have suffered terribly for want of fresh air. We have a very good system of purifying the atmosphere, but it is not sufficient owing to the long periods the boats have to stay under water, and a number of men have collapsed and died from suffocation. Indeed, one boat only escaped with more than half her crew totally incapacitated.”

I was keenly on the alert. Was I, I wondered, coming to grips at last with our problem?

“Well,” Captain A— went on, “we have been offered a new apparatus, which, if half of what the inventor tells us is true, will enable us to give the Hun a very bad time. We are assured that by its help a boat can stay under water for five days without the slightest risk.”

“Five days!” I repeated incredulously. “Why, it’s impossible!”

“So I thought,” he rejoined, “but when Engström and Linner vouch for anything, you’ve got to listen.”

“Engström and Linner!” I gasped. Things were getting “warm” indeed.

“Yes,” he replied. “Mr Engström is in Paris now with his invention, and we are going to test it off Havre.”

Then I sprang my mine. “Would you be surprised to learn,” I asked, as coolly as I could, “that your Mr Engström is not Mr Engström at all, but a German agent passing under his name?”

I have seen a good many badly surprised men in my life, but I never witnessed before or since such a spectacle of hopeless astonishment as Captain A— presented when he grasped the full significance of this announcement. He sat staring at me, his mouth wide open, and with dismay written legibly on every line of his countenance.

“But, Sant,” he gasped. “Are you sure? Mr Engström came to us in London and told us all about it. He explained that the inventor was a Spaniard who would not trust the ‘neutrality’ of the Spanish Government in the matter, and that he had brought his invention to Engström’s with the idea of getting the best terms from one of the Allies.”

“I have no doubt that the man posing as Engström came to you,” I replied. “But, none the less, he is not Engström at all.”

“Then what is his game?” countered A—. “He has offered us the fullest test before we adopt his machine, and has not asked for a cent.”

“That remains to be seen,” I answered, “but it bodes no good to the Allies. What does he propose?”

“He has offered to instal the apparatus on one of our newest types,” replied A—, “and she is on her way to Havre for the purpose. We are to make any test we like, and, in fact, I am here to see the test carried out. The only condition he makes is that his machinery shall be sealed, and not opened until after the test has proved it to be satisfactory.”

I began to see light. “Did he propose to go with you?” I asked.

“No,” replied A—, rather ruefully, I fancied. “He said the machinery was so perfect that it would practically run itself from our electric accumulators, and that he would give us an absolutely free hand with it.”

“I wonder how many of you would have come back?” I said meaningly.

A— swore fervently, and I saw by the gleam in his eyes that he was fully awake to the possibilities of the trap into which he had been so nearly led.

Our task now, barring some unforeseeable contingency, was fairly easy; there was a good prospect of ensnaring our foes in the pit they had so skilfully dug for us.

“The matter is up to you now,” I told A—. “I’m going to drop out till the very last minute. But I shall be with you then. It is of the utmost importance that we shall do nothing to scare these very wary birds. What is your plan?”

“Well,” said A—, “it seems to me I had better go ahead as if nothing had happened. The arrangement is that Engström shall take his apparatus to Havre and instal it on E77. We are then to put to sea for the tests, and are to meet him later and inform him of our decision.”

“That will do all right,” I said. “I shall come on board the submarine before Engström arrives, and then I think we shall surprise him.”

A— departed at once to make the final arrangements and I busied myself in sending off some telegrams arranging for the final downfall of the Hun plotters.

A week later I found myself on board E77 at Havre. The mysterious cases had been sent on, and with them came Engström, with Thornton and Tegelmund, who professed to be interested in the venture—the former financially, the latter as the inventor. Tegelmund was in high glee at being thus afforded an opportunity of putting his device to a thoroughly satisfactory test. We also had a big surprise in the arrival of Halbmayr, who arrived in Havre under the name of Mennier. That he should have ventured on the scene at all showed how intensely interested he was.

Engström declared that the fitting of the machinery would occupy fully three days, and we, of course, humoured him in every way possible. A— made himself particularly agreeable, playing the part of host to perfection, and it was evident that the conspirators never even dreamed that their nefarious designs were suspected by the genial naval officer who showed such an enthusiastic interest in the wonderful stories with which they plied him on the merits of their great discovery.

The three days went by. Four great cases of machinery had been duly shipped on board, and Engström, Thornton, and Tegelmund spent many hours daily at their work in the interior of the submarine. Of course I could not appear—I should have been recognised at once—but among the crew of the submarine were a couple of the smartest men of the Sûreté, who kept the bogus engineer and his associates under the closest scrutiny. They reported to me that Engström appeared to be the only one of the three with any great amount of mechanical knowledge, and that, while Tegelmund worked assiduously at his machine, the others spent most of their time carefully examining the details of the British vessel, in which they showed the greatest interest. I began to get at last an inkling of the plot!

The fourth day dawned—the day of the dénouement. Early in the morning I slipped on board the submarine, and when the two conspirators arrived we made our coup.

Engström, when he came on board with Tegelmund, found himself suddenly confronted by the Commander, with a stalwart bluejacket standing on either side of him. He was curtly informed that he could not go below.

“But you promised!” he shrieked, livid with vexation.

“True!” said the Commander. “But you call yourself Oscar Engström, of Malmö, and I happen to have the real Mr Engström here.”

The engineer went white to the very lips as Mr Engström, who had come post-haste from Stockholm in response to my urgent cable, emerged from behind the conning-tower, closely followed by myself. The false Engström began a vehement protest, but ceased suddenly, for, glancing round, he saw Tegelmund also under guard. The game was up!

A few minutes later, with Engström and Tegelmund safely in irons, the Admiralty experts who had come over from London began a minute examination of the wonderful “invention.” They soon discovered that the cases contained a jumble of wires and odds and ends of mechanical scraps simply thrown together to look complicated, and of no value whatever for the renewal of vitiated air.

The real object was only revealed when we had got to the very heart of the amazing collection of rubbish. There, cunningly hidden among much that was superfluous, was a highly efficient electric motor, wonderfully made and controlling a powerful bomb by machinery, set to detonate the explosive after six hours’ running. The machinery was to have been operated by the electric batteries of the submarine, and had the E77 gone to sea and begun the “tests” of the bogus apparatus, not a vestige of the vessel or the crew would have been seen again, and the secret of her loss would have been locked for ever in the depths of the Atlantic.

But this, we found, was only a part of the plot—perhaps even the least important part. Tegelmund, finding himself trapped, turned craven and revealed the whole story. The real object of the spies was to get the fullest possible details of the internal arrangements of a British submarine of the latest type, and how well they had succeeded was shown when we cast our net a little wider.

Directly Engström and Tegelmund were in custody, an innocent-looking signal flag flew from the masthead of the submarine, and the officials of the Sûreté ashore made their pounce. Thornton and Halbmayr were seized at once at their hotel, and in their possession we found a wonderful series of drawings in which many of the secrets of the submarine were fully explained. A telegram to Paris brought about also the arrest of Madame Bohman, and a few days later the German agents were safely immured in the convict prison at Tours, where they were sent by the sentence of a court-martial summoned immediately to deal with their case. Their guilt in this particular case was too clear for any possibility of denial, but I am glad to say that their arrest opened up a way to us to deal the Hun Secret Service a blow from which it has never fully recovered. Enormous piles of documents were seized and carefully examined, with the result that numerous associates of Thornton in England found themselves in durance vile “for the duration,” and so many fingers of the Hidden Hand were lopped off that the hand itself was badly crippled for many months to come. How the fingers grew and were again cut off I hope to tell at some later date.