“That’s what it was!” said the detective. “Like incense, yet not like it. I knelt down and listened at the grating, and I’ll swear that I heard voices. They were very faint.” “Men’s?” “No, women’s.” “Could you see anything?” “No, sir, it was a blind ventilator; there was probably a shaft there—in fact, I’m sure there was, because I pushed a stone through one of the holes and heard it drop some distance down.” “There may be an underground room there,” said Poiccart, “and somebody’s burnt joss-sticks to sweeten the atmosphere.” “Under the factory? It’s not in the plans of the building. I’ve had them from the surveyor’s office and examined them,” said George, “although surveyors’ plans aren’t infallible. A man like Oberzohn would not hesitate to break so unimportant a thing as a building law!” Leon came in at that moment, heard the story and was in complete agreement with Poiccart’s theory. “I wondered at the time we saw the plans whether we ought to accept that as conclusive,” he said. “The store was built at the end of 1914, when architects and builders took great liberties and pleaded the exigencies of the war.” Digby went on with his story. “I was going back to the barge to get past the water-gate, but I saw the old man coming down the steps of the house, so I climbed the wall, and very glad I was that I’d shifted that broken glass, or I should never have got over.” Manfred pulled his watch from his pocket with a frown. They had lost nearly an hour of precious time with their inquiries in Chester Square. “I hope we’re not too late,” he said ominously. “Now, Leon . . .” But Leon had gone down the stairs in three strides. _Chapter XXX_ _Joan a Prisoner_ DAZED with grief, not knowing, not seeing, not caring, not daring to think, Joan suffered herself to be led quickly into the obscurity of the side-street, and did not even realize that Oberzohn’s big limousine had drawn up by the sidewalk. “Get in,” said the woman harshly. Joan was pushed through the door and guided to a seat by somebody who was already in the machine. She collapsed in a corner moaning as the door slammed and the car began to move. “Where are we going? Let me get back to him!” “The gracious lady will please restrain her grief,” said a hateful voice, and she swung round and stared unseeingly to the place whence the voice had come. The curtains of the car had been drawn; the interior was as black as pitch. “You—you beast!” she gasped. “It’s you, is it? . . . Gurther! You murdering beast!” She struck at him feebly, but he caught her wrist. “The gracious lady will most kindly restrain her grief,” he said suavely. “The Herr Newton is not dead. It was a little trick in order to baffle certain interferers.” “You’re lying, you’re lying!” she screamed, struggling to escape from those hands of steel. “He’s dead! You know he’s dead, and you killed him! You snake-man!”