“What will you do?” Eliza eyed him curiously.

“Oh, I’ll follow; never fear!  If it’s not too bad, I’ll stay with the boats, of course.  But we’re not likely to have much difficulty at this season.”

Eliza noted the intensity with which the boatmen were scanning the passage ahead, and something in O’Neil’s tone told her he was speaking with an assurance he did not wholly feel.

“You have lost some men here, haven’t you?” she asked.

“Yes.  But the greater danger is in coming down.  Then we have to get out in the current and take our chances.”

“I’d like to do that!” Her lips were parted, her eyes were glowing, but Natalie gave a little cry of dismay.

“It’s an utterly new sensation,” O’Neil admitted.  “I’ve been thinking of sending you up across the moraine, but the trail is bad, and you might get lost among the alders—­”

“And miss any part of this!  I wouldn’t do it for worlds.”  Eliza’s enthusiasm was irresistible, and the expedition was soon under way again.

Progress was more difficult now, for the river-shore was paved with smooth, round stones which rolled under foot, and the boats required extreme attention in the swift current.  The farther they proceeded, the more the ice wall opposite increased in height, until at last it shut off the mountains behind.  Then as they rounded the first bend a new prospect unfolded itself.  The size of Jackson became even more apparent; the gravel bank under which they crept was steeper and higher also.  In places it was undercut by the action of the waves which periodically surged across.  At such points Murray sent his charges hurrying on ahead, while he and his men tracked the boats after them.  In time they found themselves opposite the backbone of the glacier, where the Salmon gnawed at the foot of a frozen cliff of prodigious height.  And now, although there had been no cause for apprehension beyond an occasional rumble far back or a splitting crack from near at hand, the men assumed an attitude of strained watchfulness and kept their faces turned to the left.  They walked quietly, as if they felt themselves in some appalling presence.

At last there came a sound like that of a cannon-shot, and far ahead of them a fragment loosened itself and went plunging downward.  Although it appeared small, a ridge promptly leaped out from beneath the splash and came racing down the river’s bosom toward them.

“Better go up a bit,” O’Neil called to his charges.

The men at the ends of the tow-lines scrambled part way up the shelving beach and braced themselves, then wrapped the ropes about their waists, like anchormen on a tug-of-war team.  Their companions waded into the flood and fended the boats off the rocks.

The wave came swiftly, lifting the skiffs high upon the bank, then it sucked them back amid a tangle of arms and legs.  A portion of the river-bottom suddenly bared itself and as suddenly was submerged again.  The boats plunged and rolled and beat themselves upon the shore, wrenching the anchormen from their posts.  They were half filled with water too, but the wave had passed and was scudding away down-stream.