“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.