"Now you can listen in, Doctor," announced Mostyn, after he had produced and connected up a supplementary pair of 'phones. "There's not much doing, I fancy." Selwyn adjusted the ear-pieces, while Peter, similarly equipped, stood by pencil in hand in order to give his companion some inkling of any stray message. "There's something!" exclaimed the doctor. He was excited. As cool as the proverbial cucumber when he was performing a deft and rapid operation upon which human life depended, he was now as delighted as a child with a new toy, when he heard the high-pitched buzzing sound that indicated a message in transit. "Niton," explained Peter. "Isle of Wight station. She's calling up--no--half a minute." Mostyn's pencil was moving rapidly as he recorded the message. "Cut out o.m. SOS signals out: stop sending." Then almost immediately after came a plaintive wail from a ship: "Please repeat whole of preamble and words after 'overcoat'." "Explain, please," asked Selwyn. Mostyn, busy altering the wave length in an attempt to pick up the SOS, did not reply. Explanations could come later. A vessel fifty miles away was trying to obtain a repetition of a message from Niton. Part of it she had received, but her operator was doubtful about the preamble and the words following overcoat. It was a purely private message, of no interest to anyone save the sender. Niton was trying to make the operator stop sending, as there was an SOS message coming from somewhere. The ship's operator for some reason was persisting in his inquiries for the words following overcoat. In addition a distant high-power station was chipping in, and there were also "atmospherics" of high frequency. Out of this chaotic "jam" Mostyn was trying to isolate the urgent wireless call for aid. Almost deafened by the exaggerated reverberations of the ear-pieces as Mostyn pursued his efforts to tune in, Selwyn watched with unabated interest the Wireless Officer's deft manipulations of the set. Greek the doctor understood, but this was something far beyond his ken. At last. Faintly, almost indistinguishable from the cackling of the atmospherics, came the despairing SOS. It emanated from a vessel in dire distress. Peter knew that she was using her comparatively low emergency set. That indicated the fact that her ordinary sending apparatus had broken down. "SOS. S.S. _Passionflower_ 17 miles s. by w. of Owers. Boiler explosion, ship making water rapidly; pumps inadequate." "Message received," sent Mostyn, then handing Selwyn the paper on which he had written the fateful message, "Captain, please," he said. The doctor removed his telephones and departed on his errand. Meanwhile Mostyn was listening in for other vessels in the vicinity replying to the general and urgent call for aid.