The three men, with the police chief, had taken up their head-quarters in the factory, from which the body of Gurther had been removed in the night. The Deputy Commissioner, who came on the spot at nine, and examined the dead snakes, was something of a herpetologist, and pronounced them to be veritable _fers-de-lance_, a view from which Poiccart differed. “They are a species of African tree snakes that the natives call _mamba_. There are two, a black and a green. Both of these are the black type.” “The Zoo mamba?” said the official, remembering the sensational disappearance of a deadly snake which had preceded the first of the snake mysteries. “You will probably find the bones of the Zoo mamba in some mole run in Regent’s Park—he must have been frozen to death the night of his escape,” said Poiccart. “It was absolutely impossible that at that temperature he could live. I have made a very careful inspection of the land, and adjacent to the Zoological Gardens is a big stretch of earth which is honeycombed by moles. No, this was imported, and the rest of his menagerie was imported.” The police chief shook his head. “Still, I’m not convinced that a snake could have been responsible for these deaths,” he said, and went over the ground so often covered. The three listened in polite silence, and offered no suggestion. The morning brought news of Washington’s arrival in Lisbon. He had left the train at Irun, Leon’s agent in Madrid having secured a relay of aeroplanes, and the journey from Irun to Lisbon had been completed in a few hours. He was now on his way back. “If he makes the connections he will be here to-night,” he told Manfred. “I rather think he will be a very useful recruit to our forces.” “You’re thinking of the snakes in the house?” Leon nodded. “I know Oberzohn,” he said simply, and George Manfred thought of the girl, and knew the unspoken fears of his friend were justified. The night had not been an idle one for Oberzohn and his companions. With the first light of dawn they had mounted to the roof, and, under his direction, the gunmen had dismantled the four sheds which stood at each corner of the parapet. Unused to the handling of such heavy metal, the remnants of the Old Guard gazed in awe upon the tarnished jackets of the Maxim guns that were revealed. Oberzohn understood the mechanism of the machines so thoroughly that in half an hour he had taught his crew the method of handling and sighting. In the larger shed was a collapsible tripod, which was put together, and on this he mounted a small but powerful searchlight and connected it up with one of the plugs in the roof. He pointed to them the three approaches to the house: the open railway arches and the long lane, at the end of which the crowd at that moment was beginning to gather. “From only these places can the ground be approached,” he said, “and my little quick-firers cover them!”