"By a process of elimination. They're not speaking English; they're not French. The lingo is too soft for German, so only Turkish remains. Got your revolver ready?" "Yes," said the midshipman, his nerves a-tingle. "Then don't use it unless I give the word. Slip the safety-catch and be on the safe side. We don't want an accidental discharge." Softly the Sub groped his way, Sefton following at arm's-length behind him. After traversing another fifty paces Dick stopped. Ahead he could see a mound of rubble reaching almost to the roof of the tunnel. It was night: not a star was to be seen. A driving rain was falling, while across the murky patch formed by the partly obstructed mouth of the tunnel the search-lights of the British fleet travelled slowly to and fro as they aided the mine-sweepers in their long, arduous task. Not a shot was being fired. The Turkish batteries silenced, at least temporarily, required no attention at present from the deadly British guns. The sound of the voices still continued. The speakers were chattering volubly, yet there was no sign of them. Gaining confidence, Crosthwaite advanced till farther progress was arrested by the barrier of rubble. Feeling for a foothold, and cautiously making sure that the projecting stones would bear his weight, the Sub climbed to the summit of the barrier, then, lying at full length, peered over the edge. A heavy shell had accounted for the damage done to this exit from the magazine, for a huge crater, twenty feet in diameter, yawned ten feet beneath him. Not only had the pit been torn up, but masses of rock had been wrenched from the of the cliff, as well as from the top and sides of the tunnel. On the irregular platform thus formed were nearly a score of Turkish troops--artillerymen in greatcoats and helmets somewhat similar to those worn by the British during the last Sudan campaign. With them were two officers in long grey cloaks and fezes. All seemed to be talking at the same time, irrespective of disparity in rank. Some of the men were piling sand-bags on the seaward front of the crater, others were looking upwards as if expecting something from above. Presently the expected object appeared, lowered by a powerful tackle. It was the carriage of a large field-piece. "Those fellows show pluck, anyhow," thought Dick. "After the gruelling they've had, and seeing their forts knocked about their ears, they set about to place fresh guns in position. These field-pieces, well concealed, will take a lot of finding, unless we can stop the little game." Meanwhile Sefton had climbed the barrier and lay by the side of his companion. Silently the two watched the development of the Turks' operations. They had not long to watt.