“Because,” explained Gale, “that tide don’t stop at the opening. It comes on up—perhaps a good ways. When it’s low tide there, there’s a high tide somewhere this side, and coming this way. I don’t know how fast, or how far it would come, or how far up it would close this passage. But somewhere we’ve probably got to meet that tide, and the farther up this way it is, the less likely it’ll be to rise higher than the ceiling.” I had another spasmodic seizure at this suggestion. It amounted to almost a chill, in fact, and Gale considerately waited until I was better. Then he said: “If we pass that tide all right, we’ll have a clear run for the entrance, and if I’ve counted the time right we ought to make it before it closes. Of course if there’s a head wind, or our propeller gives out—why——” “I know,” I said hastily, though with some attempt at calmness, “we wouldn’t get through.” “Oh, yes we would,” said Gale cheerfully, “we’d get through all right, but we wouldn’t be worth picking up, afterwards.” We were now at the entrance of the great tunnel. The ceiling above was a vast black arch, hollowed out by the warmer waters of the river, during its great freshets. At the opening it was very high, and the span above thin and crumbling, and hung with huge icicles. Streams of water were pouring from it, and we had barely passed beneath when just behind there came the crash of falling fragments. We were nearly upset by the upheaval of water, but were presently beyond the reach of this danger. We had turned on our light, and it threw a long white radiance ahead that dazzled back and forth, and up and down, between ice and water in a wonderful iridescence. The wide ceiling lowered rapidly until it was perhaps fifteen feet above our heads and seemed much closer. We remembered that at Bottle Bay it was less than ten, and the tides there rose very high. We were running at full speed and the current was swift. Our log showed that we were making twenty miles an hour. At this rate we believed that a little more than seven hours would bring us through. Perhaps even less than that. In spite of the vault-like cold and stillness about us, we grew mildly cheerful. “Nick,” said Gale, “we’re going home in style. What do you suppose Johnnie and Biff will say, if they happen to see us pop out into Bottle Bay, as if we’d been shot out of a gun?” The prospect seemed almost too joyful to consider. Gale, meantime, had opened one of the compartments, and brought forth a small flask containing what was left of our supply of brandy. He held it up to the light. “Just about one apiece,” he commented cheerfully. “If we get through all right, we’ll have plenty more. If we don’t we won’t need it. What is hope without a high-ball? Age before beauty, Bill, you first.” Mr. Sturritt shook his head. I think he seldom tasted liquors. “I—er—I have a few of the brown lozenges,” he explained. “They are very stim—that is—sustaining during cold, as you remember.”