It was a warm, misty dawn and the moisture-laden atmosphere was like that of a damp hothouse when Lawless arrived to start the trials. These occupied the whole morning, and at noon the Lieutenant decided on a "stand-easy" so that Cassidy might partake of the lunch he had brought with him. The Lieutenant had intended to share the repast, but that last volplane had been too much for him, and he had succumbed to his new enemy--air-sickness. While Cassidy, whose stomach was as strong as a ship's boiler, consumed his lunch Lawless pondered over his very problematical chance of ever bringing down another Zeppelin. Suddenly his thoughts were interrupted by the flickering of the needle attached to the wireless apparatus. Bending over the instrument, he realised that it was recording an urgent message for help for some vessel in distress. "S--S--S--S. Steamer _Nimrod_ attacked by submarine," he read. Then followed the latitude and longitude of the ship's position, ending up with emergency call "S--S--S." "Great Scot!" ejaculated the Lieutenant. "Did ye speak, sorr?" asked Cassidy, with his mouth full of bread and cheese. "Finish your grub, Mike; we've got a long flight in front of us," answered Lawless. He had made up his mind to go to the assistance of the distressed vessel. At a rough calculation she was about fifty or sixty miles away in a south-westerly direction, and, as the seaplane had a speed of a hundred miles an hour under favourable conditions, the Lieutenant hoped to reach her in a little over half an hour. A glance at the petrol gauges showed that the supply was running low and that there was only enough left to carry the machine seventy or eighty miles, which would mean about twenty miles short of the return journey. But Lawless, with his usual disregard for consequences, decided to deal with that problem when it arose, nor did he stop to ask himself what practical assistance he could render the _Nimrod_ when he arrived. Shouting some instructions to Cassidy, he started the engines. The great propeller began to revolve, and the seaplane, after skimming along the surface of the water for fifty yards or so, rose gracefully in the air. The conditions, apart from the haze, were excellent for flying, and, after a flight of twenty-five minutes, Lawless made out what looked like a cloud of black smoke rising vertically above the mist. A few moments afterwards he could see the hull of a large steamer with a heavy list to starboard and so low down at the bows that her propellers were raised above the water. The Lieutenant at once volplaned to the surface, hoping that he might catch sight of some of the ship's boats, which, no doubt, had been launched as soon as the vessel was struck by the torpedo. But the low-lying mist, much thicker here than near the coast, prevented his seeing anything outside a very narrow radius.