A sudden inspiration flashed across Mostyn's mind. In the stern-sheets of the lifeboat was a box containing amongst other things a Verey's pistol. It was a weapon not of offence but for humane purposes. It was fired by means of a cartridge, but, instead of a bullet, it sent up a vivid coloured light to a height of about two hundred feet. Peter stooped and opened the lid of the box. Thank Heaven! The pistol and cartridges were there. Deftly he opened the breech and thrust home the cardboard cylinder containing the detonator and explosive light; then, standing on the stern bench and steadying the tiller with one foot, he levelled the short-barrelled weapon. For some seconds he waited. The shark in its orbit was immediately between the lifebuoy and the boat. Preston and his companion were in as much danger from the pistol as they were from the shark. The huge fish dived and soon reappeared, this time well to the left of the buoy. It had partly turned on its back, and its wide-open jaws, triple lines of pointed teeth, and greenish-white belly were clearly visible, for by this time the whaler was less than twenty-five yards away. It was now or never. The shark was preparing to make a dash for its victims under the bows of the boat. Deliberately Peter pressed the trigger. He had to guess for elevation, knowing nothing of the trajectory of the missile. His aim was good. The rocket must have disappeared down the capacious maw of the shark, for there was no sign of the fiercely burning rocket sizzling on the surface. The satisfactory part of the business was that the shark disappeared and was seen no more. Quickly the two men were hauled into the boat, both bordering on a state of collapse. Then, ordering the lascars to give way, Mostyn steered for the _West Barbican_, picking up the jettisoned lifebuoys on the way. He was one who always finished a job properly. CHAPTER XV Unpopularity A few days later Mostyn was having an easy time. He was on watch, but with little to do. A notice-board on the promenade-deck furnished the reason for his enforced inactivity: "S.S. _West Barbican_. To-day, in radio communication with _nil_. To-morrow, radio communication expected with _nil_." The notice was painted with the exception of the two _nils_, which were written in chalk. Placed for the convenience of passengers wishing to send off private wireless messages, it duly recorded what ships and shore stations were within radio range. In her present position in the South Atlantic she was too far away to dispatch or pick up messages from Cape Town, the radius of her wireless being limited to 240 miles by day and almost thrice that distance by night. Peter had overhauled the set, and was taking the opportunity of writing home. With his white patrol-coat unbuttoned and his _solar topee_ perched on the back of his head, he was making the best of things in spite of the terrific heat and the attentions of numerous cockroaches.