“I left my light in the stateroom.  I’ll go and——­”

But the lieutenant never finished that sentence.  Across the dark and silent ocean came a dull report—­an explosion that seemed to make the Jeanne tremble.  And then the sky and the water was lighted by the flashing beams of powerful lights.

“What was that?” gasped Joe, while from the crouching figures in the bow came exclamations of dismay.  “Are we torpedoed?”

“I fancy not,” answered Blake.  “Sounded more like one of the destroyers made a hit herself.  I think they set off a depth charge against a submarine.  We’ll soon know!  Look at the lights now!”

The sea was agleam with brilliant radiance.

CHAPTER XII

IN ENGLAND

From the bridge came commands to the lookouts stationed in various parts of the French steamer.  Orders flashed to the engine room, and the vessel lost way and floated under her momentum.  As yet she was shrouded in darkness, the only lights glowing being those actually required to enable persons to see their way about.  Below, of course, as long as the incandescents were shaded, they could be turned on, and many passengers, awakened by the concussion and the following sounds, illuminated their staterooms.

The lights that gleamed across the billows came from the convoying destroyers, and signals flashed from one to the other, though the meaning of them the moving picture boys could only guess at.

Immediately following the explosion, which seemed to come from the side of the Jeanne where Labenstein had flashed his signal, the German and the Frenchman had subsided into silence.  Each one had given voice to an exclamation in his own tongue and then had hurried away.

And so occupied were Blake and his chums with what had gone on out there on the ocean—­trying to guess what had happened—­that they did not notice the departure of the two men.

“What’s that you said it was?” asked Joe of his partner.  “I mean the explosion.”

“I think it was a depth charge,” answered Blake.  “One of the destroyers must have sighted a submarine and let go a bomb, with a heavy charge of explosive, which didn’t go off until after it got to a certain depth below the surface.  That’s the new way of dealing with submarines, you know.”

“I only hope they got this one, with a depth charge or any other way,” remarked Charles Anderson.  “Look, we’re lighting up!  I guess the danger must be over.”

Lights were flashing on the deck of the Jeanne, and signals came from the destroyers.  It was evident that messages were being sent to and fro.

And then, as passengers crowded up from their staterooms, some in a state of panic fearing a torpedo had been launched at the ship, another muffled explosion was heard, and in the glare of the searchlights from one of the convoying ships a column of water could be seen spurting up between the French steamer and the war vessel.