Decks that, a moment, before, had exhibited scenes of quietness, though there was a nervous tenseness on all sides, at once assumed feverish activity. Officers on duty, hearing the cry of the lookout, called to him to repeat his message, which he did, with the added information that the submarine, as evidenced by the appearance of the periscope cutting the water, was approaching nearer, and with great swiftness.

"Here she comes, Blake!" cried Joe, as the two boys stood together at the spot from which they had been watching the wireless messenger a moment before. "Here she comes! Now for a chance at a picture!"

"You're not going below, are you?" cried Blake.

"Why not?" asked Joe, pausing on his way to the companionway.

"Why, we may be blown up at any moment! We may be hit by a torpedo! I don't see why they haven't loosed one at us before this, as their periscope is in sight. You shouldn't go below now! Stay on deck, where you'll have a chance to get in the boat you're assigned to!"

"I've got to go below to get the small camera," answered Joe. "I ought to have kept it on deck. I'm going to, after this, to have it ready."

"But, Joe, the torpedo may be on its way now—under water!"

"That's just what I want to get a picture of! I guess if we're going to be blown up, being below deck or on deck doesn't make much difference. I want to get that picture!"

And, seeing that his chum was very much in earnest, Blake, not to let Joe do it alone, went below with him to get the camera. But on the way they met Charlie coming up with it.

"She's all loaded, boys, ready for action!" cried the lanky Macaroni. "I started down for it as soon as I heard the lookout yell! I didn't know what he was jabbering about, seeing I don't understand much French, but I guessed it was a submarine. Am I right?"

"Yes!" shouted Joe. "Good work, Mac! Now for a picture!"

And while Joe and his two friends were thus making ready, in the face of imminent disaster, to get pictures of the torpedo that might be on its way to sink the ship, many other matters were being undertaken.

Passengers were being called to take the places previously assigned to them in the lifeboats. Captain Merceau and his officers, after a hasty consultation, were gathered on the bridge, looking for the first sight of the submarine, or, what was more vital, for the ripples that would disclose the presence of the torpedo.

But perhaps the most eager of all, and certainly among the most active, were the members of the gun crews. On both sides of the vessel, and at bow and stern, the call to quarters had been answered promptly, and with strained but eager eyes the young men, under their lieutenants, were watching for the first fair sight of something at which to loose the missiles of the quick-firing guns.

"Give it to her, lads! Give it to her! All you can pump in!" yelled the commander of the squad on the port side, for it was off that bow that the lookout had sighted the periscope.

And while the hurried preparations went on for getting the passengers into the lifeboats, at the falls of which the members of the crew stood ready to lower away, there came from the port gun a rattle and barking of fire.

The periscope had disappeared for a moment after the lookout had sighted it, but a slight disturbance in the water, a ripple that was different from the line of foam caused by the breaking waves, showed where it had been.

And by the time Joe and Blake, with the help of Charlie, had set up their small camera, the tell-tale indicator of an undersea boat was again in view, coming straight for the steamer.

"There she is!" cried Blake.

"I see her!" answered Joe, as he focussed the lens of the machine on the object "I'll get her as soon as she breaks!"

The mewing picture boys, as well as Charlie, had forgotten all about the need of taking their places at the stations assigned to them, to be in readiness to get into a boat. They were sharply reminded of this by one of the junior officers.

"Take your places! Take your places!" he cried.

"Not yet!" answered Joe. "We want to get a shot at her first!"

"But, young gentlemen, you must not shoot with that. It will be ineffectual! Let the gunners do their work, I beg of you. Take your places at the boats!"

"That's all right!" exclaimed Blake "We're only going to shoot some moving pictures."

"Ah, what brave rashness!" murmured the French officer, as he hurried away.

Blake and Joe, with Charlie to steady the machine, for the steamer was now zigzagging at high speed in an effort to escape the expected torpedo, were taking pictures of the approach of the submarine. The underwater craft was still coming on, her periscope in the midst of a hail of fire from the steamer's guns. For, now that the vessel was making turns, it was possible for two gun crews, alternately, to fire at the German boat.

"There goes the periscope!" yelled Charlie, as a burst of shots, concentrated on the brass tube, seemed to dispose of it.

But he had spoken too soon. The submarine had merely drawn the periscope within herself, it being of the telescope variety, and the next moment, with a movement of the water as if some monster leviathan were breaking from the ocean depths, the steel-plated and rivet-studded back of the submarine rose, glistening in the sun and in full view of those on deck, not two hundred yards away.

"There she blows!" cried Charlie, as an old salt might announce the presence of a whale. "There she blows! Film her, boys!"

And Blake and Joe were doing just that.

Meanwhile even wilder excitement, if possible, prevailed on deck. There was a rush for the boats that nearly overwhelmed the crews stationed to lower them from the sides, and the officers had all they could do to preserve order.

"The torpedo! The torpedo at the stern!" cried the lookout, who, notwithstanding his position of almost certain death should the ship be struck, had not deserted his elevated post. "They have loosed a torpedo at the stern!"

Blake and Joe, who were well aft, looked for a moment away from the submarine, and saw a line of bubbles approaching the stern and a ripple that indicated the presence of that dread engine of war—an air-driven torpedo.

And as if the ship herself knew what doom awaited her should the torpedo so much as touch her, she increased her speed, and to such good purpose that the mass of gun-cotton, contained in the steel cylinder that had been launched from the submarine, passed under the stern. But only a few feet from the rudder did it pass. By such a little margin was the ship saved.

And then, having a broader mark at which to aim, the gunners sent a perfect hail of lead and shells at the underwater boat, and with such effect that some hits were made. Whether or not they were vital ones it was impossible to learn, for there was a sudden motion to the submarine, which had been quietly resting on the surface for a moment, and then she slipped beneath the waves again.

"Driven off!" cried Blake, as he and Joe got the final pictures of this drama—a drama that had come so near being a tragedy. "They've beaten her off!"

"But we're not safe yet!" cried Charlie. "She may shoot another torpedo at us from under water—she can do that, all right! Look out, boys!"

There was need of this, yet it was impossible to do more toward saving one's life than to take to the boats. And even that, under the inhuman and ruthless system of the Huns, was no guarantee that one would be saved. Lifeboats had, more than once, been shelled by Germans.

The appearance of the submarine had added to the panic caused by the sight of the periscope, and there was a rush for the boats that took all the power and authority of the officers to manage it.

There was a period of anxious waiting, but either the submarine had no other torpedoes, or, if she did fire any, they went wide, or, again, the gunfire from the vessel may have disabled her entirely. She did not again show herself above the surface. Even the periscope was not observed.

Having nothing to picture, Blake and Joe turned away from the camera for a moment. Some of the lifeboats had already been filled with their loads when Charlie, pointing to something afar off, cried:

"Here comes another boat!"

On the horizon a dense cloud of black smoke showed.