For three long days the Dart bore away northwest, the direction in which the last had been seen of the missing boat.

"Luckily it's the right course to steer for the Siberian coast," remarked the captain, as he sat over his wine after midday dinner. "We shall sight the high land to-morrow morning, if not before"

"Surely we shall come across the boat in time, captain?" remarked Bob.

"Well, we have had wonderfully fine weather," replied the captain. "But, after all she was but a cutter, handled by a lunatic."

And he and Bob interchanged looks of despair as they ascended the companion ladder.

"Bok, go to the foremast-head," ordered the captain. "Take the glass, and have a look around."

The sailor slung the telescope over his shoulder and nimbly mounted the rigging.

When he arrived at the topgallant-yard he passed his arm round the skypole, and, adjusting the glass, swept the line of the horizon.

There was a long pause.

"Deck ahoy!"

"What is it?" bellowed the captain.

"Sure, there is a mist, or smoke right ahead, and above it I see what looks like the top of a mountain," replied the Irishman.

"Nothing else?"

"There is a low, flat berg."

"Nothing more? No sign of a boat-sail?"

"Nothing the size of a pocket handkerchief, yer honor."

"Well, we must give up the search for the present and start for the Siberian shore. But I give you my word, Bob, I shall not give up this hunt for many a week."

The wind fell light, and the Dart did not make more than three knots an hour during that afternoon.

The strange misty appearance still hung over the water.

They were gradually approaching it, and it was not more than a couple of miles ahead............