"Monsieur Escoltier," said the editor. A few seconds later the door was opened, and a man was ushered into the room. Short and thick-set, with a two days' growth of beard on his chin, his nationality was apparent long before he spoke in the _argot_ of the lowly born Parisian. His face was haggard, his eyes heavy from lack of sleep, and the hand that strayed to his mouth shook tremulously. "I have to tell you," he began, "about M'sieur Moss and M'sieur Hyatt." His voice was thick, and as he spoke he glanced from side to side as though fearful of observation. There was something in his actions that vividly reminded the detective of his interview with Hyatt. "You understand," the man went on incoherently, "that I had long suspected N.H.C.--it was always so unintelligible. There was no such station and----" "You must calm yourself, monsieur," said T. B., speaking in French; "begin at the beginning, for as yet my friend and myself are entirely in the dark. What is N.H.C., and what does it mean?" It was some time before the man could be brought to a condition of coherence. The editor pushed him gently to the settee that ran the length of the bay window of his office. "Wait," said the journalist, and unlocking a drawer, he produced a silver flask. "Drink some of this," he said. The man raised the brandy to his lips with a hand that shook violently, and drank eagerly. "C'est bien," he muttered, and looked from one to the other. "I tell you this story because I am afraid to go to the police--they are watching the police office----" "In the first place, who are you?" demanded T. B. "As to who and what I am," said the stranger, nodding his head to emphasise his words, "it would be better that I should remain silent." "I do not see the necessity," said the detective calmly. "So far as I can judge from what information I have, you are a French soldier--an engineer. You are a wireless telegraph operator, and your post of duty is on the Eiffel Tower." The man stared at the speaker, and his jaw dropped. "M'sieur!" he gasped. "Hyatt was also a wireless operator; probably in the employ of the Marconi Company in the west of England. Between you, you surprised the secret of a mysterious agency which employs wireless installations to communicate with its agents. What benefits you yourself may have derived from your discovery I cannot say. It is certain that Hyatt, operating through Moss, made a small fortune; it is equally certain that, detecting a leakage, the 'Nine Men' have sent a clever agent to discover the cause----" But the man from the Eiffel Tower had fainted. "I shall rely on you to keep the matter an absolute secret until we are ready," said T. B., and the editor nodded. "The whole scheme came to me in a flash. The Eiffel Tower! Who lives on the Eiffel Tower? Wireless telegraph operators. Our friend is recovering." He looked down at the pallid man lying limply in an armchair.