Keeping a sharp look-out for the approach of Hun reliefs along the corridor, the two officers waited until the pungent fumes had almost cleared. Then, into the suffocating atmosphere they penetrated. Ascending the short flight of steps they gained the gun emplacement. The weapon, trained to the extreme left, was pointing slightly to the right of the lighthouse, at the extreme end of the Mole extension. Around it lay the bodies of the crew. A glance through the sighting-slit in the gun-shield gave Alec a clue. Seaward the water was swept by search-lights, the giant beams darting between the sullenly rolling clouds of artificial fog. Quick-firing guns were blazing away like fury. Apparently a torpedo-craft attack on the harbour was about to take place. "Make a job of it while we are about it," shouted Smith, pointing to a passage on their right. "Another quick-firer in there!" Through the passage dashed the impromptu bombers, encouraged by their previous victory. Less than ten yards away was another 15-centimetre gun. Apparently its crew were either in ignorance of the knocking-out of the sister-gun, or else they attributed the noise of the bombs to the explosion of a shell fired from seaward. In any case the surprise was complete. Two bombs were sufficient to silence the weapon. Beyond was yet a third gun. In this instance the task was by no means so easy, for running along the communication passage came a stalwart naval gunner--one of a picked crew from the German High Seas Fleet. It was the two officers' canvas suits--garments so grudgingly accepted and yet so opportune--that saved them from instant detection. The Hun, imagining them to be two members of a working-party, bellowed an incoherent order. In a trice he was collared in approved Rugby fashion, while a heavy blow behind the ear reduced him to a state of insensibility. The scuffle was witnessed by two or three Germans engaged in bringing up ammunition. Their shouts of alarm roused the rest of the gun's crew. Before Seton and his companion, having completed their task of strafing the Hun gunner, could hurl their bombs, a fusillade of pistol shots rang out. A bullet grazed Smith's cheek; another ploughed a furrow through Seton's hair. The pilot threw a bomb full in the face of a Prussian unter-leutnant. The missile failed to explode, although it floored the German. Another Boche picked up the bomb and hurled it back. Ricochetting against the wall it hurtled past Seton's head and clattered on the floor of the tunnel ten feet in the rear of the British officers. There was no time to devote to that. If the sinister missile exploded it meant an end to the contest, but fortunately it was what was known as a "dud".