One could not see it.  Only it was as if the ring of sea to windward had of a sudden grown smaller.  Heidrek was not a mile astern of us, and still his ships were in bright sunshine.  Even as we watched them, a grayness fell on them, and then they grew dim.

Then the fog closed in on us, and swallowed us up, and drifted across the decks so thickly that we could barely see from gunwale to gunwale, damp, and chilling.  Still, the wind did not fail us, hurrying the fog before it.

“We must hold on until we know if this is but a bank of fog, or if it is everywhere,” Bertric said.  “What say you, Malcolm?”

I thought a while, knowing the cold sea fogs of the north pretty well.

“Heidrek will be in it by this time,” I said.  “Fog bank or more, I would about ship and run back past him with the wind.  If it is a bank, we shall go with it, and he must lose us.  If it is more, we can get on our southward course in it shortly, and if he sights us again, he will have all his work to catch us, for his men will be tired of rowing.”

“What if the fog lifts directly?”

“We shall be little worse off than now—­and we shall be heading down on Heidrek before he knows it.”

“Aye,” he answered, “with way enough on us to sink him offhand, and maybe take this ship clear through his.  Get to the sheets, you and Dalfin, and we will chance it.”

Bertric luffed, and we hauled the tack amidships.  Then he paid off to the wind, and we slacked off the sheet with the help of a turn of its fall round the great cleat of the backstay.  The wash of the waves round the bows ceased, and there was only the little hiss of the water as the sea broke alongside of us.  It always seems very silent for a little while when one puts about for a run after beating to windward.

“Listen,” said Bertric under his breath, “we shall hear Heidrek directly on the starboard bow somewhere.  Pray Heaven he has not changed his course, or we shall hit him!  He will not have luffed any more, for certain.”

“Suppose he thinks that we have tried some such trick as this?” said Dalfin.

Bertric shook his head.

“He thinks we shall go on as we steered, making for the Norway shore.  It is likely that he will think that we may have paid off a bit, for the sake of speed.  Even if he did think we were likely to do this, what could he do?  He cannot tell, and to put about and run on the chance would be to give away his advantage if we had held on after all.  Listen!”

“I hear him,” said Gerda, who was leaning on the gunwale with parted lips, intent on catching any sound.

The sound she had heard came nearer and nearer as we slid silently through the water into the blinding fog.  It was like a dull rumble at first, and then as a trampling, until the roll and click of the long, steadily pulled oars was plain to us.  The ship was passing us, and not more than an arrow flight from us.  It seemed almost impossible that we should not see her.