He ceased speaking, and sat watching the other boat making, like themselves, slowly for the same point. And now, seeing the urgency, Johannes and his brother Norsemen seated themselves and put out spare oars to help on the speed. But the whale they were towing seemed to anchor them in one place; and at last, just as the steamer was still quite half a mile away, a peculiar change came over the sea. The sun was still shining brightly, but the other boat grew dim and enlarged-looking, as if it were magnified and set in a bluish opal. There was the long range of ice cliff, but it was curiously blue and undefined. "I say," cried Steve suddenly, "what's the matter with the _Hvalross_?" He started from his seat as he spoke, for the steamer was no longer upon the blue water,--there was no blue water,--but apparently twenty feet up in the air, and gradually rising higher till it was double the height, while the funnel, masts, and hull looked soft and swollen out of all proportion. "An optical illusion, my boy," said the captain quietly. "Sit down. You have heard of refraction. It is a peculiar state of the air. I daresay we look the same to them. Pull, my lads. I'm afraid the mist will be down upon us before we can reach the ship. Look at that." Steve was already looking at the peculiar way in which their companion boat was dying out of sight, till it was perfectly invisible; and yet it was clear about where they were, only for a few minutes, though. Then there was a faint, gauzy film close by, into which they rowed, and as they passed completely in, the _Hvalross_ was almost hidden; five minutes later it was not to be seen. The mist was upon them, thickening each moment, and a curiously depressing chill came over the boy. It was as if the cold were attacking his mind as well as his body, and he quite started as the deep voice of Johannes said, the words sounding muffled: "Keep your helm fast, sir. We mustn't miss the ship." "Mustn't miss the ship," thought Steve, with a strange sense of dread creeping over him now like another and darker mist. "If we did miss her, what then?" CHAPTER TWELVE. A STRANGE PERIL. It seemed hard to believe, so rapidly had the change taken place. Only a few minutes before, and they were gliding along with the blue sky above and the air perfectly clear; now everything was shut out, even Johannes in the bows of the boat looking indistinct from where Steve and the captain were seated in the stern. Captain Marsham made no verbal reply to the warning of the Norseman, but his right arm which held the steering oar grew rigid, and he did not stir from his position.