When the boys arose the following morning, each somewhat stiff and sore from the experiences of the night before, it was with a feeling of happy anticipation that made their physical discomforts seem like trivial things.

For before nightfall the twin screws of the large transport Everett would begin to churn the waters of the Delaware, her bow would be pointed down stream, and the great voyage of adventure would be started.

But in the meantime there was much for the lads to learn. Up to the present every moment had been occupied to the exclusion of such instructions as were absolutely necessary to know, in order that they might give the best service to their country.

And so they responded early to a summons from the superior officer in charge of men in the Signal Corps at that station. By him they were informed of the serious mission upon which they were bound, and of the responsibilities that would fall upon them should the transport, by any mishap, become separated from its armed convoy.

No message picked up at sea or elsewhere, he told them, was to be repeated to anyone but the superior officer to whom it was directed; and any calls for another vessel or station were to be ignored by them, even if their aerial should pick the words up.

They were told of the fine loyalty demanded of men in their branch of the service, and given some idea of the sacrifices they might be called upon to make.

"The success of this war," said Major Briggs, "depends upon the courage and ability with which each man in it performs the immediate task before him. Whether the whole world shall fall under the iron hand of a merciless tyranny, or the peoples of the various nations may govern themselves in the freedom of democracy, now depends largely upon the men of the United States. We must regard the responsibilities thrust upon us as a glorious opportunity to serve all of mankind."

Thrilled with the nature of the great work ahead of them, Joe, Jerry and Slim hurried down the long length of the navy yard to where the Everett lay moored to her slip, the center of much activity.

Steam already was up, as they could see from the thick black clouds of smoke that curled upward from her smokestack. Big cranes, operated by powerful winches on the vessel and on shore, were hoisting cases of various sizes and shapes upon the lower decks and into the hold. A small army of men helped complete the loading of the ship, and one group was experiencing considerable difficulty in trying to persuade unwilling mules to board the transport for Europe.

The boys hurdled over piles of food and ammunition, wended their way through scores of stacks of ordnance, and finally over a gang-plank to the vessel. There they saluted and reported to the officer of the day, who directed them to go at once to the wireless room.

As they entered there Lieutenant Mackinson was busily engaged in "tuning up" his instruments. He stopped when he saw them and reached into an inner pocket, from which he produced three large oblong envelopes. One was addressed to each lad, and as they accepted them they saw that each was closed to prying eyes by the official seal of Uncle Sam.

Swept by various emotions, the boys stood there gazing first at the envelopes and then at Lieutenant Mackinson.

"Well," said the lieutenant at last, with an amused smile, "do you want me to retire while you read your communications?"

"Oh, no, not at all, sir," Joe hastened to say, and as if to prove the statement all three envelopes were ripped open and the single sheet of paper in each drawn forth.

Especially addressed to each lad, the letters were identical and read:

The letters were signed by the commandant of the Philadelphia Navy Yard.

"Look at that," said Slim, pushing his letter at Lieutenant Mackinson, utterly forgetful of the fact that the other man was his superior officer. "Ain't—isn't that fine, though? For the commandant to mention it that way, I mean."

"Yes," admitted Lieutenant Mackinson, "but he wouldn't have mentioned it that way if you hadn't deserved it."

"I'm not going to lose that letter," announced Jerry.

"Nor I," added Joe, "although we only did what any other fellows would have done under the same circumstances."

"Well," said Lieutenant Mackinson, "it showed that you were to be depended upon in an emergency, and emergencies are likely to crop up at any time in our work, so let's get down to business."

He immediately began explaining the apparatus of the wireless room—how messages were sent and received; the power of the batteries and their auxiliaries; the switch-board regulating voltage; the automatic recording apparatus—in fact, every detail connected with the intricate mechanism of an up-to-date wireless.

"There was a time," explained Lieutenant Mackinson, "when the sending of a message almost deafened the sender. It was like being in the midst of a machine-gun assault. But recent improvements have eliminated that. You may see for yourselves."

And the lieutenant tapped off the Everett's own signal call with little more sound than is made by the sending of a message with the ordinary telegraph instrument.

"We have a sending and receiving radius of from five hundred to eight hundred miles," Lieutenant Mackinson continued. "Of course, it doesn't compare with the great wireless station at Radio, Virginia, one of the largest in the world, where one tower is six hundred feet high and the other four hundred and fifty feet in height, and each charged with two hundred thousand volts, giving a radius of three thousand miles; but it is sufficiently powerful for practically every purpose required at sea."

"Wasn't Marconi a wonderful man?" said Jerry in true admiration.

"Yes, he was; no doubt of that, and he still may contribute much to the science, for he is not old yet," the young lieutenant answered. "But still, full credit must be given where credit is due, and in that respect it must be acknowledged that Marconi only assembled and perfected to practicable purposes the discoveries and inventions made before his time.

"Radio-telegraphy might be briefly traced in the names of Faraday, Maxwell, Hertz—the discoverer of the Hertzian rays—Righi, Lodge and Marconi. All of them contributed something to the evolvement of the present highly efficient and dependable wireless. Marconi should, and does, receive great credit; but the others, the pioneers, the real discoverers, should not be forgotten or overlooked."

The lieutenant's words threw a new light on the history of the wireless for the boys from Brighton, and they were anxious that the officer should tell them more; but at that moment Lieutenant Mackinson caught the faint recording of a distant wireless call for another station, far down the Atlantic coast.

"Here," he said hastily, turning to Joe, who was nearest him, "see if you can catch this message."

He slipped the receiving apparatus over Joe's head, and tightened up the ear-pieces, then pushed toward him a pad and pencil.

Into Joe's ears came the faint but distinct sounds of a distant call:

-· ··· -· ··· -· ···

"N S," Joe jotted down on the sheet before him.

"A ship at sea calling Newport News," Lieutenant Mackinson informed the other two, who waited impatiently for Joe to begin recording the message.

Newport News acknowledged the call, and then the vessel's wireless continued:

·--- ·- ··· ·--· · ·-·

And Joe, transcribing, wrote: "JASPER." Following this came:

-·· · - ·- ·· ·-··

The other boys looked on in chagrin, while Lieutenant Mackinson's countenance took on an amused smile, as Joe wrote down the word "DETAIL," and then nothing else but the initials "N. N.," which ended the message.

"Don't make sense," announced Slim in a discouraged voice. "You must have missed part of it."

"No, I didn't," Joe replied, looking anxiously toward the lieutenant.

"I guess he got it all," the young officer assured them, at the same time unlocking a little closet and taking a leather-bound book from an upper shelf. "Let's see."

He turned to the J's and ran his finger down the page until he came to the word "JASPER."

"That means 'We have coaled,'" he said, writing the words out on the pad.

"Oh, it's in code," said Slim apologetically; "I didn't know that."

"DETAIL," the lieutenant announced, finding that word. "'Understand and am following sealed orders'. That's the North Dakota. She has coaled at sea and is now starting upon some mission known only to her commander and the naval authorities."

Almost as he finished speaking the Everett gave a lurch, her whistle was tooted two or three times, the engines started turning, and the big boat began to vibrate under the pressure.

There was a shout from the thousand or more who had crowded to the river's edge, responded to by the fifteen hundred khaki-clad young men who were lined up at every point of vantage along the vessel's side.

"And we're off, too," shouted Lieutenant Mackinson.

"Hurrah!" cried the three boys from Brighton in the same breath, as they double-quicked it behind the lieutenant to the upper deck.

The scene was one to inspire the most miserable slacker. Somewhere in the upper part of the yard a band was playing Sousa's "Stars and Stripes Forever." From the windows of the ordnance and other buildings at the lower end of the yard workmen hung forth, waving hats and handkerchiefs, and joining in the shouted well-wishes of those along the shore. The crews of every fighting craft in that part of the river sang out friendly advice to those aboard the transport, and two miles down the channel could be discerned the smoke from the stacks of the armed convoys that were to give the Everett safe passage to her destination.

Among those at the water's edge the boys could discern the big form of Sergeant Martin, and even as distance welded them in an indistinguishable mass, they could still see him, towering above the others, his hat describing wide circles through the air.

"So long, fellows; we'll meet you over there," shouted the men of the last vessel they passed.

As though by prearrangement the fifteen hundred men on the Everett began singing, "I'm Going Over," sang it to the end of the first verse, then stopped, and from a point well down the river could hear those they had passed taking up the second stanza.

Hours later, out upon the ocean, the dim lights ashore fading one by one, the fighters for Uncle Sam gave one last, long, lingering look at their native land. And Jerry, voicing the spirit of all, cried out:

"Farewell, United States."