Steve was no experienced sailor, but he had seen plenty of the last fog, and as he sat there growing anxious the following problem presented itself to him after the fashion of the mathematical studies at school, and based on the difficulty of making a way through what was little better than black darkness. Let A, B, and C represent the points of a triangle. If three parties start together from those points to reach a common centre, and travel at different rates of speed, when will they meet?

“It looks as if the answer is—never,” thought Steve. “Why, the Hvalross is steaming faster—we saw her; and she’ll go right on and leave us behind. This fog, too, may last for days.”

“Keep cool, my lad,” said the captain in a low voice; “we shall soon be on board. Listen, and try if you can hear the beat of the propeller.”

Those words sent a hopeful thrill through the boy, just as his spirits were getting very low indeed, and he leaned over the boat’s side listening, but the regular dip, dip of the oars was all he could distinguish. He did not speak; there was no need.

“Steady!” cried the captain suddenly, and his voice sounded as if it were shut in. “Lie on your oars for a few moments. Listen for the beat of the steamer.”

There was dead silence then, and Steve began to realise for the first time in his life the meaning of the word “lost.”

But no sound came to their ears from out of the mist which now surrounded them, and seemed to arch them in as if they were in a dark grey cell just big enough to hold the boat.

“Had we better cast off the fish, sir,” said Johannes at last, “and pull hard?”

“No,” said Captain Marsham; “matters are not so desperate as that. Here, Steve boy, your voice is the youngest and most likely to pierce the mist; give a good ahoy.”

“Ahoy!” yelled the boy, and again, “Ahoy! ahoy!” but the hail sounded as if he were shouting with his head closely shut in a box, and all felt that it was useless to listen for a reply.