“About there.” Barnes indicated a point north of the Azores. “But this atlas is too small to see it. Send someone to my room for my large atlas. You’ll see better on that.”
French having telephoned his instructions Barnes went on.
“She’s evidently lying on what is called the Dolphin Rise. The Dolphin Rise is part of a great ridge which passes down the middle of the Atlantic from near Iceland to well down towards the Antarctic Ocean. This ridge is covered by an average of some 1,700 fathoms of water, with vastly greater depths on either side. It is volcanic and is covered by great submarine mountain chains. Where the tops of these mountains protrude above the surface we get, of course, islands, and the Azores are such a group.”
A constable at that moment entered with the large atlas, and Barnes continued:
“Now we’ll see in a moment.” He ran his finger down the index of maps, then turned the pages. “Here we are. Here is a map of the North Atlantic Ocean: here are the Azores and hereabouts is your point, and—By Jove!” the young man looked actually excited, “here is what your cipher means all right!”
The other three crowded round in almost breathless excitement. Barnes pointed with a pencil slightly to the east of a white spot about a quarter of an inch in diameter which bore the figure 18.
“Look here,” he went on, “there’s about the point she is supposed to have sunk. You see it is colored light blue, which the reference tells us means over 1,000 fathoms. But measure one degree to the west—it is about fifty miles at that latitude—and it brings us into the middle of that white patch marked 18. That white patch is another mountain chain, just not high enough to become an island, and the 18 means that the peaks come within 18 fathoms of the surface. So that your cipher message is probably quite all right, and your Antwerp party are more than likely working away at the gold at the present time.”
French swore comprehensively.
“You must be right,” he agreed. “One can see now what that blackguard of a U-boat commander did. He evidently put some men aboard the Silurian to dismantle their wireless, then made them sail on parallel to his own course until he had by the use of his lead maneuvered them over the highest peak, and then put them down. The whole thing must have been quite deliberate. He returned to his own government a false statement of her position, which he knew would correspond with the last message she sent out, intending it to be believed that she was lost in over 1,000 fathoms. But he sank her where he could himself afterwards recover her bullion, or sell his secret to the highest bidder. The people on the Silurian would know all about that two or three hours’ steam west, so they must be got rid of. Hence his destroying the boats one after another. No one must be left alive to give the thing away. To his own crew he no doubt told some tale to account for it, but he would be safe enough there, as no one except himself would know the actual facts. Dirty savage indeed!”
With this speech of French’s a light seemed to Cheyne suddenly to shine out over all that strange adventure in which for so many weeks he had been involved. With it each puzzling fact seemed to become comprehensible and to drop into its natural place in the story as the pieces of a jigsaw puzzle eventually make a coherent whole. He pictured the thing from the beginning, the submarine coming up with the ship in deep water, but comparatively close to a shallow place where its treasure could be salved: the desire of the U-boat commander, Schulz, to save the gold, quite possibly in the first instance for the benefit of his nation. Then the temptation to keep what he had done secret so as, if possible later, to get the stuff for himself. His fall before this temptation, with its contingent false return to his government as to the position of the wreck. Then, Cheyne saw, the problem of passing on the secret in the event of his own death would arise, with the evolution and construction of the cipher as an attempted solution. As a result of Schulz’s fatal wound the cipher was handed to Price, and Schulz was doubtless about to explain how it should be read, when he was interrupted by the nurse. Before another chance offered he was dead.