As the men looked they knew it to be true; the channel was certainly narrower than when they first rose upon its surface.
Securing a light line, the Doctor attached it to a plummet. Throwing the plummet across the space, he drew the line taut. He then marked the point where the ice-line crossed it. Then for five minutes he divided his attention between the line and his watch. As he rose he muttered;
"Two hours! Two hours! How long will it take to complete the repairs?"
"Four hours, at least," Dave replied calmly.
"Then we're defeated!" The Doctor began pacing the surface of the ice. "We're stuck—beaten! In two hours the channel will be closed, and there is not another patch of open water within five miles!"
If Dave seemed unnaturally calm on receipt of such news, it was because he had in his "bag of tricks" one of which the Doctor was not aware. While in Nome he had made the acquaintance of a former British seaman, who had cruised Arctic waters in the late eighties, when Japan was disputing the rights of Great Britain and the United States to close the seal fisheries. This man had told him how the gunboats had opened their way through the ice-floes. The idea had appealed to the young skipper. Consequently, on boarding the submarine, he had carried under his arm a package which he handled very carefully, and finally deposited in the very center of a great bale of fur clothing. There it still remained.
"I suppose I might tell him," he said to himself. "But I guess I won't. 'Blessed is he that expecteth nothing,' The trick might not work. I'll wait." He turned to where the mechanics were hard at work adjusting the new propeller.
The repairing had gone on for something over two hours. The water-channel had completely closed. The Doctor was pacing the ice, lost in reflection. Like a flash, there came into Dave's mind a new problem: would the current be content merely to close the channel, or would the ice soon begin to buckle and pile? With an uneasy mind, he urged the workmen to hasten, at the same time keeping an eye on the line of ice where the channel had so lately been.