Gladys was not slow to note the stress that Burke laid on the last word.

"Oh, impossible," she began hurriedly, "impossible that he could have known anything about this other matter. Why, she told me he was to sail suddenly for Germany and came up here for a last visit before he went, and to arrange to come back on his return. Oh, he could know nothing--impossible."

"Why impossible?" persisted Burke. "They have submarines in Germany, don't they? And rival companies, too."

"Who have rival companies?" inquired a familiar voice. It was Captain Shirley, who had returned out of breath from his long climb up the steps from the sh.o.r.e.

"The Germans. I was speaking of an attache named Nordheim."

"Who is Nordheim?" inquired the captain.

"You met him at the Naval building, that night, don't you remember?"

replied Gladys.

"Oh, yes, I believe I do--dimly. He was the man who seemed so devoted to Mrs. Brainard."

"I think he is, too, father," she replied hastily. "He has been suddenly called to Berlin and planned to spend the last few days here, at the hotel, so as to be near her. She told me that he had been ordered back to Washington again before he sailed and had had to cut his visit short."

"When did you first notice the interference with the Turtle?" asked Burke. "I received your message this morning."

"Yesterday morning was the first," replied the captain.

"He arrived the night before and did not leave until yesterday afternoon," remarked Burke.

"And we arrived to-night," put in Craig quietly. "The interference is going on yet."

"Then the j.a.ps," I cut in, at last giving voice to the suspicion I had of the clever little Orientals.

"They could not have stolen the plans," a.s.serted Burke, shaking his head. "No, Nordheim and Mrs. Brainard were the only ones who could have got into the draughting room the night of the Manila celebration."

"Burke," said Kennedy, rising, "I wish you would take me into town.

There are a few messages I would like to send. You will excuse us, Captain, for a few hours? Good evening, Miss Shirley." As he bowed I heard Kennedy add to her: "Don't worry about your father. Everything will come out all right soon."

Outside, in the car which Burke had hired, Craig added: "Not to town.

That was an excuse not to alarm Miss Shirley too much over her friend.

Take us over past the Stamford cottage, first."

The Stamford cottage was on the beach, between the sh.o.r.e front and the road. It was not a new place but was built in the hideous style of some thirty years ago with all sorts of little turned and k.n.o.bby ornaments.

We paused down the road a bit, though not long enough to attract attention. There were lights on every floor of the cottage, although most of the neighbouring cottages were dark.

"Well protected by lightning-rods," remarked Kennedy, as he looked the Stamford cottage over narrowly. "We might as well drive on. Keep an eye on the hotel, Burke. It may be that Nordheim intends to return, after all."

"a.s.suming that he has left," returned the secret-service man.

"But you said he had left," said Kennedy. "What do you mean?"

"I hardly know myself," wearily remarked Burke, on whom the strain of the case, to which we were still fresh, had begun to tell. "I only know that I called up Washington after I heard he had been at the hotel, and no one at our headquarters knew that he had returned. They may have fallen down, but they were to watch both his rooms and the emba.s.sy."

"H-m," mused Kennedy. "Why didn't you say that before?"

"Why, I a.s.sumed that he had gone back, until you told me there was interference to-night, too. Now, until I can locate him definitely I'm all at sea--that's all."

It was now getting late in the evening, but Kennedy had evidently no intention of returning yet to Lookout Hill. We paused at the hotel, which was in the centre of the cottage colony, and flanked by a hill that ran back of the colony diagonally and from which a view of both the hotel and the cottages could be obtained. Burke's inquiries developed the fact that Nordheim had left very hurriedly and in some agitation. "To tell you the truth," confided the clerk, with whom Burke had ingratiated himself, "I thought he acted like a man who was watched."

Late as it was, Kennedy insisted on motoring to the railroad station and catching the last train to New York. As there seemed to be nothing that I could do at Lookout Hill, I accompanied him on the long and tedious ride, which brought us back to the city in the early hours of the morning.

We stopped just long enough to run up to the laboratory and to secure a couple of little instruments which looked very much like small incandescent lamps in a box. Then, by the earliest train from New York, we returned to Lookout Hill, with only such sleep as Kennedy had predicted, s.n.a.t.c.hed in the day coaches of the trains and during a brief wait in the station.

A half-hour's freshening up with a dip in the biting cold water of the bay, breakfast with Captain Shirley and Miss Gladys, and a return to the excitement of the case, had to serve in place of rest. Burke disappeared, after a hasty conference with Kennedy, presumably to watch Mrs. Brainard, the hotel, and the Stamford cottage to see who went in and out.

"I've had the Z99 brought out of its shed," remarked the captain, as we rose from the breakfast-table. "There was nothing wrong as far as I could discover last night or by a more careful inspection this morning.

I'd like to have you take a look at her now, in the daylight."

"I was about to suggest," remarked Kennedy, as we descended the steps to the sh.o.r.e, "that perhaps, first, it might be well to take a short run in her with the crew, just to make sure that there is nothing wrong with the machinery."

"A good idea," agreed the captain.

We came to the submarine, lying alongside the dock and looking like a huge cigar. The captain preceded us down the narrow hatchway, and I followed Craig. The deck was cleared, the hatch closed, and the vessel sealed.

XX

THE WIRELESS DETECTOR

Remembering Jules Verne's enticing picture of life on the palatial Nautilus, I may as well admit that I was not prepared for a real submarine. My first impression, as I entered the hold, was that of discomfort and suffocation. I felt, too, that I was too close to too much whirring machinery. I gazed about curiously. On all sides were electrical devices and machines to operate the craft and the torpedoes.

I thought, also, that the water outside was uncomfortably close; one could almost feel it. The Z99 was low roofed, damp, with an intricate system of rods, controls, engines, tanks, stop-c.o.c.ks, compa.s.ses, gauges--more things than it seemed the human mind, to say nothing of wireless, could possibly attend to at once.

"The policy of secrecy which governments keep in regard to submarines,"

remarked the captain, running his eye over everything at once, it seemed, "has led them to be looked upon as something mysterious. But whatever you may think of telautomatics, there is really no mystery about an ordinary submarine."

I did not agree with our "Captain Nemo," as, the examination completed, he threw in a switch. The motor started. The Z99 hummed and trembled.

The fumes of gasoline were almost suffocating at first, in spite of the prompt ventilation to clear them off. There was no escape from the smell. I had heard of "gasoline heart," but the odour only made me sick and dizzy. Like most novices, I suppose, I was suffering excruciating torture. Not so, Kennedy. He got used to it in no time; indeed, seemed to enjoy the very discomfort.

I felt that there was only one thing necessary to add to it, and that was the odour of cooking. Cooking, by the way, on a submarine is uncertain and disagreeable. There was a little electric heater, I found, which might possibly have heated enough water for one cup of coffee at a time.

In fact, s.p.a.ce was economised to the utmost. Only the necessaries of life were there. Every inch that could be spared was given over to machinery. It was everywhere, compact, efficient--everything for running the boat under water, guiding it above and below, controlling its submersion, compressing air, firing torpedoes, and a thousand other things. It was wonderful as it was. But when one reflected that all could be done automatically, or rather telautomatically, it was simply astounding.

"You see," observed Captain Shirley, "when she is working automatically neither the periscope nor the wireless-mast shows. The wireless impulses are carried down to her from an inconspicuous float which trails along the surface and carries a short aerial with a wire running down, like a mast, forming practically invisible antennae."

As he was talking the boat was being "trimmed" by admitting water as ballast into the proper tanks.

"The Z99," he went on, "is a submersible, not a diving, submarine. That is to say, the rudder guides it and changes the angle of the boat. But the hydroplanes pull it up and down, two pairs of them set fore and aft of the centre of gravity. They lift or lower the boat bodily on an even keel, not by plunging and diving. I will now set the hydroplanes at ten degrees down and the horizontal rudder two degrees up, and the boat will submerge to a depth of thirty feet and run constant at that depth."

He had shut off the gasoline motor and started the storage-battery electric motor, which was used when running submerged. The great motors gave out a strange, humming sound. The crew conversed in low, constrained tones. There was a slightly perceptible jar, and the boat seemed to quiver just a bit from stem to stern. In front of Shirley was a gauge which showed the depth of submergence and a spirit-level which showed any inclination.

"Submerged," he remarked, "is like running on the surface under dense-fog conditions."