The uppermost one was a general map of the coast, including Haddisport and Buremouth, with the villages between and a wide strip of the sea, divided into numbered sections. The others—and there were some twenty of them—were detailed enlargements of the same sections, upon which were shown the principal buildings of the two towns, the particulars of the harbours and railways, with every road and lane and bridge, every field and coppice and house, distinctly indicated.
Mark Redisham had never seen such wonderful maps, or imagined that any existed so complete and correct. Nothing seemed to have been overlooked. On the margins of each sheet were notes, written in German, with numbers referring to certain features in the plans.
Mark saw much that he did not then understand; but there was one sheet in particular which was perfectly clear to him. It was a large scale chart of the section of the North Sea immediately facing Haddisport, giving the exact soundings of the channels and shallows and showing an outline of the coast, with every altitude measured.
The soundings of Alderwick Knoll were so precise and plentiful that it was evident to him that some important purpose was connected with this sand-bank. He could hardly doubt, indeed, that the chart had been prepared for the guidance of an enemy attempting an invasion!
So greatly was he impressed by this idea, that he became nervously excited over his discovery. What was he to do? Should he carry these charts and maps away with him, now—to-night? He had not been instructed to take anything away with him; but only to "have a look round" and report upon any discovery he might happen to make.
Thinking over the situation for a few swift moments, he determined to obey his orders to the letter. Accordingly, he returned the sheets to the map-case, put the case back where he had found it, and prepared to leave the loft.
He left no trace of his secret visit. Taking his cap and pocketing his torch, he climbed down the ladder into the garage. He pushed lightly at the door; but it did not swing open. He pushed it harder; still it resisted. Then he put his shoulder to it and gave it a shove. It did not move. He grappled with it, trying with all his strength to force it open and, realised, to his alarm, that it had been locked from the outside!
He grew hot and cold by turns. Had he been watched, stealing into these stables where he had no business which he could truthfully explain? If so, who could it be that had watched and trapped him? It could not be Heinrich Hilliger himself, or Max. Herr Hilliger had gone back to Germany. Max was drowned. The chauffeur had not returned with the car. Once more he put his shoulder to the door. No. It was certainly locked! He was a prisoner!
But Mark Redisham was not a Sea Scout for nothing. There were more ways than one of getting out. He tried the door of the harness-room. That, too, was locked. Yet there was still another door, leading into the stable. It opened with a simple latch and he crossed to the door giving on to the yard. Again he was foiled.
He looked to the window. It was heavily barred.