"Diving stations!"
The H29 was once more submerged. There was a cloud of smoke on the horizon which might be from the funnels of an enemy cruiser. Seen afterwards in the periscope mirror, however, the stranger turned out to be a British liner. The ballast tanks were blown out, and the submarine rose awash. The electric motor had stopped and the petrol engine had not yet been set in motion. Instead of the telegraph signifying "go ahead!" there came an ominous rasping sound from the neighbourhood of the forward torpedo-chamber. Something was wrong!
"Sounds as if we'd fouled some wreckage," conjectured the chief engineer, standing by his cranks and levers with his eye on the dial.
Mark Redisham was astonished to hear his name called from the conning-tower. He followed three of the men who also had been summoned. When he came out into the open air he discovered Mr. Ingoldsby and Mr. Desmond standing together looking forward along the narrow strip of deck to where a great round shape lay jammed between the hydroplane and its guard.
"It's a German mine!" cried Mark. "Don't let it be moved, sir. Wait! Keep the engines stopped! You've fouled its mooring; but it won't go off—it won't explode—unless one of the horns gets broken or bent."
"That's what I judged," nodded Lieutenant Ingoldsby, looking very grim. "But how is the thing to be cleared away if we don't move it? You know the tricks of these things. What do you advise?"
"Wait a bit, sir," urged Mark. He stooped and quickly took off his boots and stockings. "Let me go along and have a close look at it."
"No, I can't let you," objected the commander. "It's too dangerous."
"Then let one of the men come with me, sir," Mark suggested, not at all alarmed.
Before he could be stopped, he had slipped past the men and was making his way along the wet and slippery platform. Mr. Desmond, also in bare feet, went after him. They reached the place where the mine was lodged. The horns of the deadly machine were fortunately all pointed outward. The mooring line of flexible wire rope had been caught as the submarine rose to the surface and was securely fixed in the hydroplane bearings, held by its own weight and the weight of the sinker.