The spy went to one of the windows. The air was still sharp but mild in comparison to the piercing cold of the night. Already the sun was well above the horizon. Two thousand feet or less beneath the airship--for on approaching land the Zeppelin had descended considerably--could be discerned with remarkable clearness the green grass and red sandstone of the island of Heligoland with a strand of white sand adjoining one face of the cliffs. A short distance beyond was the flat, semi-artificial island of Sandinsel, with its batteries, concealed when viewed from the sea, standing conspicuously against the dunes. Still further away were the flat, receding shores bordering the estuary of the Elbe, but vainly the spy looked for any signs of the vaunted High Seas Fleet. Even the well protected triangular expanse of water was desolate of shipping, save for a few small craft engaged either in laying additional mines or conveying stores to the island fortress. At that height the varying depths of the sea could be noted owing to the changing colour of the water--not that that fact interested von Eitelwurmer in the slightest. He was a landsman out and out. He was content to leave the difficult task of wresting the trident from Britannia's grasp to others. The matter did not concern him. He specialised in the arts and intrigues of espionage. Von Loringhoven was cast in a different mould. Although his present energies were centred upon the air service he was at heart a seaman. He, too, was examining the expanse of sea, but with the skill of a practised navigator. "Look!" he exclaimed, pointing to a small, indistinct object from which emanated two ever-diverging lines of ruffled water. "Do you know what that is? Here, take these binoculars and look. Now, perhaps, you see what I mean?" The spy brought the glasses to bear. "A fish, I suppose," he remarked. "A fish of sorts," added the ober-leutnant. "One's sense of proportion is deceived at this height. It is an unterseeboot. I do not fancy it is ours, otherwise why should she keep submerged when close to our territorial water?" He lifted the receiver of the telephone. "Wireless cabin. Report to the commandant of Heligoland that there is a submarine in the south channel. Ask if it is one of our unterseebooten." In a few minutes came the reply. "No German submarine operating sub merged off the fortress. Can you attack?" "No, I cannot," declared von Loringhoven bluntly, directing his remarks to his companion. "She's a British submarine. Those fellows nose their way everywhere. She, evidently, is inside the outer minefield. And they want me, crippled as this airship is, to attack. It is unreasonable; besides, the wind is increasing in strength and we have yet to make a landing."