“I don’t see what that has to do with phosphorescent ink,” he said. “The police went all into the matter of his death, and they said it was just death by paralysis.” He stopped and shut his mouth hard. Dorothy broke in. “Mr. Swenton, here is the state of affairs. I don’t think my brother has made it quite plain. We are more interested in Dr. Heidenmuller’s radio-active work than in his phosphorescent paint. We have no question of you at all. We do not want to know anything which is not entirely right for us to know, but we do want to know all you feel you can rightly tell us of his work. I feel sure that my brother will be ready to employ you, if you can show that you have done this, and that you can do what he wants.” The man’s face cleared. Dorothy’s words were more convincing than evidence. He reached into his pockets and drew forth a bunch of papers, which he gave to Tom, who rapidly ran through them. “They’re all right,” he said, handing them back. “Now, if I give you twenty pounds a month for two months, will that be all right?” A dull red rose in the man’s face as his eyes lighted. “It will mean everything to me, sir,” he said. “I’ve got a wife and a boy.” Tom drew out his purse. “Here’s ten pounds to clinch the bargain,” and he handed him two five pound notes. “I appreciate that more than I can say,” said the man, the tears welling up into his eyes with emotion. “Now, what did you want to know?” “First about Dr. Heidenmuller’s apparatus, and then about his death.” “I’m afraid I can’t tell you much of the apparatus. I never even saw it. It was in an inner room to which the doctor had the only key. I never was in the room till the day we broke down the door and took him out dead. There was no apparatus there then. It must have been removed.” “How did the room look?” asked Dorothy. “It was all bare. Nothing in it at all, except the wooden chair where he sat and a wooden table.” “How about the walls and ceiling?” “They were all of wood.” “How about the locks on the door and windows?” “That was a funny thing. They were of wood, too, though he had an iron key.” “What did the doctor have in his pockets?” “Four five-pound notes, no change, and his watch was gone. There was nothing in his watch pocket except a watch crystal. His keys were gone, too, and only the ribbon of his watch was left lying on the floor.” “What did the doctors say about his death?” “Straight paralysis, they said. I had been away for three days. He was around the laboratory for one day after I left, and the day after that he must have died. They said death was instantaneous.” “Did the doctor leave any family?” “None.” “What became of his papers?” “Nobody knows. He had scarcely any friends. His property went to a niece in Germany, and she came over to hunt for papers, but she found none.” “What became of the other assistant?” “He went back to Germany. He knew nothing more than I did, however.” “Did the doctor have any friends who came to see him?”