Mid-afternoon the _Nemo_ had arrived from her home base in Long Island Sound and was awaiting now the morning to begin operations on the foundered German submarine. There had remained before sundown only a brief time for a superficial examination of the sea bottom, but in that time Jay Thacker and Dick Monaghan, crack divers of the Bridgeford Company, had donned diving armor and spent an hour under water. Imagine the surprise of the navy officials when these two youths had returned to the deck to report they could find no trace of the lost U-boat! "I don't quite understand this at all," remarked Lieutenant-Commander Wilberforce, U. S. N. He and Captain Austin were conferring together on the U. S. S. _Monadnock_, the destroyer. "Our men declare positively that this is the identical spot where the U-boat was located by divers some time ago," explained the officer. "We have not been sending divers down these last few weeks since the department ordered us to wait until they sent salvage facilities. But we have stood guard here continually and can assure you absolutely that no foreign salvage corps has been working here." Captain Austin ventured the opinion that the U-boat had been broken up by the shifting waters during a recent ten-day gale that had raged up and down the coast. "No, I hardly think so," hazarded Commander Wilberforce. "When last our divers were down they reported the U-boat well above sea bottom. It's a mystery to me." "Perhaps the German craft has been covered up with drifted sand," suggested Captain Austin. Wilberforce thought that over for a moment. "That hadn't occurred to me," he resumed after a moment. "There may be something to that. You see, we are just off the Delaware River breakwater and there are all kinds of cross-currents here." For an hour or more the two officers discussed the project and collaborated on their plans for the morrow. "I've got some pretty good divers with me," said Captain Austin as he made ready to return to the _Nemo_ for the night. "I'll stack them against anything in the world. If they can't find that U-boat then nobody can find it." "Good enough, I'm sure they'll do their best." Commander Wilberforce had thought well of Jay and Dick, and had so expressed himself during the afternoon as he saw the boys in action. With the morning sun the boys were up and ready for the day's explorations. They were anxious to get down to business. And furthermore, they were anxious that one or the other should get the first assignment of the day. Weddigen was along, but Captain Austin had not ordered him into diving armor the previous afternoon, and the Brighton boys were hopeful that the task of searching for the U-boat was to be entrusted to them alone.