“We’ve had unexampled good weather so far, Mr. Hampton,” said Farnum. “But this fog may mark the breaking-up. We may be in for it from now on.”

“I realize all that,” Mr. Hampton said, his slight impatience mute evidence to Jack, at least, that his Father was worried. “What I’d like to know now, is whether to move on or wait till the fog lifts.”

“Why not move on, Dad?” asked Jack.

“Oh, you boys up, hey? Well, for one thing, if we travel in this fog we run the danger of being caught in rapids and sucked forward before being able to reach the bank. For another, we might—just might—pass Thorwaldsson, in the fog, without knowing it. He might be traveling, too.”

After some further discussion, it was decided the party should remain until the fog lifted, and that all should be on guard to catch any sound of movement out of the fog which would indicate somebody, presumably Thorwaldsson, was passing. Following breakfast, in fact, all but Mr. Hampton, who remained in camp, as a guide in case the others blundered and lost their way in the fog, took up positions along the bank of the river, some twenty yards apart to maintain “listening posts.”

An hour passed, and then another, with no indication that the fog was thinning out, and with no sound coming to straining ears except the lap of the water along the rocks at their feet. It was nerve-trying work in a way, to sit there for so long a period, isolated, as if entirely alone in an unpeopled world. The boys, at their various stations, felt the strain considerably, more so, indeed, than did Farnum or Art who were old hands at the wilderness game.

In assigning all their stations, Mr. Hampton had decided, because of the greater experience of the two older men, that they should take up their positions at the south end of the line. If any party south-bound along the Coppermine escaped the attention of the boys, Farnum and Art would be pretty likely to remedy the oversight.

To Bob fell the most northerly position. And, as he sat there, hunched up on a rock, staring out into that thick greasy wall of mist, he felt, if anything, more lonely than his companions. Jack and Frank, at least, had the consolation of knowing there was someone to either side. But, with none of his friends beyond him on the north, Bob felt very much alone, indeed.

All sorts of reflections entered his mind, reflections that had no bearing whatsoever on the situation in which he found himself. He thought of sunny days on Long Island, of flights in his airplanes or zipping trips along the coast in his speed boat. He thought of one thing and another, classroom, Mexican mountains, that strange city of another world found immured in the Andes, and—of Marjorie. Ever since his first meeting with his sister’s friend, Miss Faulkner, she had occupied a position of growing importance in Bob’s scheme of things. Someday——

“Some girl,” Bob said to himself. “I’ll have to see more of her.”