He sat up, and at once discovered that the pyjama suit he was wearing was not his own; then he became aware that his head was throbbing painfully, and on raising his hand to the aching place his fingers encountered a strip of plaster. Then the details of the collision flashed across his mind, and the anxious question rose to his lips: "Where's Jack?" Steadying himself by grasping the rounded edge of the bunk, Gerald leant sideways. The effort nearly caused him to lose his balance, but the result of his investigations showed that the lower bunk was unoccupied. For the space of quite five minutes the injured officer lay still, striving to collect his thoughts as to where and when he last saw his late companion. Above the centre of the top bunk was an open scuttle, through which the salt-laden breeze whistled like a youthful whirlwind. From where he lay Tregarthen could see that the thickness of the vessel's side at this opening was at least 7ins.--a truly enormous size for the plating of any but a powerful war vessel, and even then it was unusual to continue the armoured belt so far above the water-line. Curiosity prompted the sub-lieutenant to essay another change of position. This time he met with better success, and was able to look through the narrow, circular aperture. [Illustration: The mast snapped off close to the deck, and a block, hurtling through the air, struck Gerald a terrific blow over the head.] His eyes dilated with astonishment. The fog had completely vanished, and the sun shone brilliantly from an unclouded sky upon the deep blue waters. But the change in the atmospheric conditions was not the cause of the young officer's surprise; it was the apparent motion of the water. Without the faintest suspicion of a bow-wave--at least as far as Tregarthen could judge--the huge vessel was tearing through the sea at a terrific rate. Taking into consideration the height of the scuttle above the sea-level, Gerald came to the conclusion that the craft was a cruiser of the largest type, yet in spite of her size he estimated her speed at not less than forty-five knots. The _Calder_, lightly built as she was, could not attain that rate, her greatest pace being a good thirty-eight knots. And with this extraordinary speed there was a total absence of vibration or noise, save the howling of the wind caused by the vessel's own motion, while the faint pulsation of the engines, that had first betrayed her presence in the fog, had entirely ceased. Then Tregarthen made another discovery. The mysterious vessel was, as far as he could judge by the position of the sun, heading nearly south-west. That meant that, willing or unwilling, he was being spirited away from the shores of Old England at a phenomenal speed--but whither?