Throwing himself flat upon the float and grasping one of the supports with his left hand, the A.P. hung as far in front as he possibly could without losing his balance. His outstretched hand came in deliberate contact with the drifting horror. The smooth, slimy surface--for the mine had evidently been in the water for some time--offered no resistance, and he thrust until his fingers "brought up" against one of the horns. How far short of the minimum pressure required to snap the brittle projection and allow the chemicals contained therein to ignite Kirkwood was never to know. He was just aware that either the seaplane or the mine was swinging clear--perhaps it was a mutual "get out of my way" affair. Scraping the for'ard outer corner of the float by a bare six inches the infernal contrivance, fended off by the A.P.'s outstretched hand, glided past, until with a sigh of relief the observer watched it disappear in the darkness. For quite a minute he hung on, his heart beating like a piston, his eyes peering through the blackness ahead. Floating mines, he knew, were generally in considerable numbers. The fact that one peril had been averted was no guarantee that all danger from these jettisoned cylinders of potential death was over. "Where the Christopher Columbus are you, old bird?" exclaimed Fuller, who, pausing in his work, had missed the rest of the "crew." "What, down on that float? What's wrong now?" "We nearly bumped into a mine," reported the A.P. "The beastly thing was within six inches of my nose." "A miss is as good as a mile," remarked the pilot nonchalantly. "If the thing had gone up six inches or six feet wouldn't have made any difference. They wouldn't have found either of us, and there wouldn't be enough of the pair of us to make a satisfying meal for a solitary North Sea herring. Look here. Up with you and give me a hand at filling the tank. I want to test my handiwork." By the time the repairs were completed to the satisfaction of all hands, grey dawn was breaking over the wild North Sea. As far as the eye could penetrate the haze that hung about in detached patches the expanse of water was unbroken. Not a sail of any description was in sight and the beetling cliffs of the Yorkshire coast had long since dipped beneath the horizon. "Fill her right up now," continued the pilot, indicating the repaired tank. "It's lucky we had so many spare tins of stuff on board. We'll mop up most of the petrol during the plug home against the wind, I reckon." Fuller, deep in final adjustments, and Kirkwood hard at work emptying the contents of the petrol-cans into the tank, were unaware of the new menace that threatened them, until a huge grey shape loomed up within fifty yards to windward of the seaplane. The shape was a German submarine mine-layer, She was running awash, while on the short, narrow platform in the wake of her conning-tower stood a couple of officers and a half a dozen seamen.