Twenty minutes later, another wireless report came through from the seaplanes. It was to the effect that neither was able to approach the fugitive pirate. If they attempted to do so their engines failed, but as soon as the pirate craft drew away there was no further trouble until they again overhauled their quarry. Lieutenant-Commander Trehallow was obviously perplexed. At first inclined to imagine that the series of forced descents was due to accident, he had at last to admit that on the face of things the seaplanes were under some unknown adverse influence. He therefore gave the airmen instructions to keep the pirate craft within sight, but not to close, until the destroyers came within visual distance of their foe. Then, rather than risk having to stop and pick up a couple of disabled aircraft, he would order them to return to their parent ship, the light cruiser _Basilikon_. At length the masts and funnel of the fugitive ship appeared over the horizon. The destroyers, hard on her track, were now rapidly overhauling her, It was a question whether they would get within striking distance before dark. The odds were against that, for the sun was now only a few degrees above the horizon. Meanwhile, all preparations were being made for a night encounter. Battle lanterns were provided in the event of the electric lamps being put out of action; night sights were attached to the guns; the parachute star-shells were taken from the magazine and the searchlights prepared for use. The sun dipped. The short tropical twilight gave place to intense darkness. The moon was not due to appear for another couple of hours, and in that time the pirate vessel might have found an opportunity to evade pursuit. There was no doubt that she was attempting to do so; but she had overlooked one important circumstance--her phosphorescent wake. Miles astern, clearly defined on the surface of the dark water, was a faint luminous trail and to this the avenging destroyers kept, like bloodhounds to a strong scent. Suddenly a vivid flash of reddish light sprang out of the darkness ahead. A shell whined through the air, throwing up a column of spray two hundred yards on the _Messines_' port quarter. "Six-inch, by the sound of it," commented Lieutenant-Commander Trehallow. "We've found her this time. On searchlights!" CHAPTER XXII Flying-boats _v._ Destroyers Two dazzling beams from the _Messines_' bridge leapt across the waste of dark water. The _Armentières_' searchlights were almost immediately switched on, and the four powerful rays swept inquiringly in the direction from which the flash of the hostile quick-firer emanated.