In less than two hours the destroyers, with their respective strings of towed boats, arrived at the British port and the work of transferring the rescued to shore began. Dan's dead and wounded were also sent ashore. It was afterward reported that nine human beings were unaccounted for. Four more died in the boats on the way to land. While the transfers to shore were being made Dan Dalzell came aboard the "Grigsby" to greet his chum. They chatted while the damaged bridge was being repaired. "Danny-boy," Dave remarked seriously, "that exploding mine showed us clearly what is expected of us. It is our task to see that all these near-by waters are cleared of such dangerous objects." "Surely we cannot get every mine that the Huns plant," objected Dalzell. "We must get as many of them as we can. I know that all the British mine-sweepers are constantly on the job, but if necessary we must have more mine-sweepers. We must keep the paths of navigation better cleared than proved to be the case to-night." "Oh, say!" expostulated Dalzell, his eyes wide open, "we simply cannot, even with twice as many mine-sweepers, find every blooming mine that the Huns choose to sow in the Channel and North Sea." "To find and take up every mine should be our standard," Dave insisted, "and we must live as close to that standard as we possibly can." "Then we did wrong to go after the destroyers this night?" Dan demanded, curtly. "Of course not, for that bombardment of that defenseless little town, carried on longer, might have cost as many lives as are likely to be lost in the case of a steamship hitting a floating mine." "We can't do everything at the same time," Dan contended. "Then we must strive to do ninety-nine per cent. of everything," Darrin urged, his jaws set. "Danny-boy, I feel as badly as you do when a single innocent life is lost in the area that we are held responsible for." "How soon do you put for sea?" Dalzell asked. "As soon as our boats return and are hoisted on board." Darrin was as good as his word. Twenty-one minutes later, while dawn was still invisible, the two Yankee destroyers turned seaward again. There was more work, and sterner, for them to do, and it lurked just beyond! CHAPTER V EYES THAT LOOKED DOWN FROM THE AIR DAWN found the two destroyers cruising slowly northward, a little more than a mile apart. Within sight of the bridges of the two craft were eight small, snub-nosed mine-sweepers. Frequently changing their course, these little craft were doing their utmost to pick up any mine that may have been planted just far enough under water to be struck below the water line by passing vessels. "I suppose we're of the few who have ever seen the flash of an exploding floating mine," Dave remarked to Lieutenant Fernald. "The sea was so rough and choppy, last night, that the mine, at the instant of impact, happened to be in the trough of the sea and partly above water."