To the spy the outlook resembled the view from a railway carriage when dense clouds of steam waft past the windows. So powerful were the rays of the searchlights that the stratum of the vapour was flooded with silvery luminosity, while--ominous sign--the beams no longer swayed to and fro as previously, but hung with sinister persistence upon the bank of clouds with which the airship hoped to screen herself from observation. Even as von Eitelwurmer looked a huge dark shadow eclipsed the concentrated beams. It was moving slowly at a rate hardly exceeding that of the airship. For that reason the object could not be an aeroplane. Perhaps it was some deadly invention that the English had brought into action against the Zeppelins--a sort of aerial torpedo steered by wireless electric waves? The machine-gunners saw it too. The last atom of courage literally oozed out of their boots, yet almost automatically they gripped the handle that would liberate shots at the rate of 500 a minute if to the voidless night. It was fortunate for them that they did not open fire. The shadow was that of another Zeppelin that at less than a hundred feet below was slowly forging ahead in a southerly direction under the action of her throttled-down motors, and with her exhausts carefully muffled. In five minutes the novel Zeppelin eclipse was over, although at no time was the actual airship to be seen. She had previously been fired upon by the anti-aircraft guns on the coast and was now cautiously smelling her way through the clouds in order to find an undefended gap in the defences. Another half-hour passed in acute suspense, Three times the anxious crew heard the terrifying sound of an aerial propeller. Somewhere in the darkness the British hornets were up and searching for their lurking foe--so far without success unless the moral effect be taken into consideration. Presently the Zeppelin drifted beyond the glare of the fixed searchlights, but not until another twenty minutes had passed did von Loringhoven give orders for the engines to be restarted. At that terrific altitude the noise was considerably diminished in volume. Instead of the explosions of the motors resembling a succession of rifle-shots the sounds were like those of a whip being cracked, yet as the airship descended steadily to a height of five thousand feet the noise resumed its normal and distracting violence. The spy sat down again. His torpor was returning. The sudden change of altitude had resulted in a steady flow of blood from his nose, while his ear-drums throbbed until they seemed on the point of bursting. At that moment he felt that he would not have minded had the airship been blown to atoms. But the next instant his lassitude vanished, as the loud pop-pop-pop of two of her machine-guns roused him from his stupor. The weapon on the starboard side was trained as far as possible abaft the beam and was pumping out nickel into the darkness.