As the pair stood whispering, a big Airedale suddenly bounded forth, barking angrily as a preliminary to attacking them. It was an exciting moment. But in that instant Ella recognised the bark as that of her father's dog. "Jack!" she said, in a low voice of reproof. "Be quiet, and come here." In a moment the dog, which Drost had evidently lent to his friend Ortmann as watch-dog, bounded towards his mistress and licked her hand. It was evident that the occupiers of the lonely place did not desire intruders. Fearing lest the barking of "Jack" might have alarmed the inmates, they remained silent for a full quarter-of-an-hour, and then again creeping beneath the shadows of the hedges and trees, they managed to cross the lawn and the gravelled path, until they stood together beneath the front of the house. "Listen!" gasped Kennedy, grasping the girl's arm. "Do you hear anything?" "Yes--a kind of muffled crackling noise." "That's a wireless spark!" her lover declared. "So they have wireless here!" Creeping along, they passed the main entrance and gained the other side of the house where, quite plainly, there could be heard the whir of a dynamo supplying the current. But though Kennedy's keen eyes searched for aerial wires, he could discover none in that dim light, the moon having now disappeared entirely. So he concluded that they were so constructed that they could be raised at night and lowered and concealed at daybreak, or perhaps even disguised as a portion of wire fencing. "As the wireless is working--sending information to the enemy without a doubt--then our friend Ortmann is most probably at home," whispered the flying-man. "As the motor is still running it will drown any noise, and we might get inside without being heard. Are you ready to risk it?" "With you, dear, I'll risk anything that may be for my country's benefit," she declared. Then he pressed her soft hand in his, stooping till his lips met hers. As they stood there in that single blissful moment, there came the sound of a train suddenly emerging from a long tunnel in the side of the hill in the near vicinity, and with the light of the furnace glaring in the darkness it sped away eastward. Its sound showed it to be a goods train--one of the many which, laden with munitions from the Midlands, went nightly towards the coast on their way to the British front. Only then did they realise that the railway-line ran along the end of the grounds, and that the mouth of the great G--Tunnel was only five hundred yards or so from where they stood. Kennedy took from his pocket a small jemmy in two pieces, which he screwed together, and then began to examine each of the French windows which led on to the lawn. All were closed, with their heavy wooden shutters secured. The shutters of one, however, though closed, had, he saw by the aid of his flash-lamp, not been fastened. The dog, Jack, following his mistress, was sniffing and assisting in the investigation.