Dangle left the room, returning presently with the blue-gray sheet which had been the pivot upon which all the strange adventures of the little company had turned. Cheyne saw at a glance it was the tracing which he had secured in the upper room in the house in Hopefield Avenue. There in the corners were the holes made by the drawing-pins which had fixed it to the door while it was being photographed. There were the irregularly spaced circles, with their letters and numbers, and there, written clockwise in a large circle, the words: “England expects every man to do his duty.” Cheyne gazed at it with interest, while Dangle and Sime sat watching him. What on earth could it mean? He pondered awhile, then turned to his companions. “Have you not been able to read any of it?” he queried. Dangle shook his head. “Not so much as a single word—not a letter even!” he declared. “I tell you, Mr. Cheyne, it’s a regular sneezer! I wouldn’t like to say how many hours we’ve spent—all of us—working at it. And I don’t think there’s a book on ciphers in the whole of London that we haven’t read. And not a glimmer of light from any of them! Blessington had a theory that each of these circles was intended to represent one or more atoms, according to the number it contained, and that certain circles could be grouped to make molecules of the various substances that were to be mixed with the copper. I never could quite understand his idea, but in any case all our work hasn’t helped us to find them. The truth is that we’re stale. We want a fresh brain on it, and particularly a woman’s brain. Sometimes a woman’s intuition will lead her to a lucky guess. We hope it may in this case.” He paused, then went on again: “Another thing we tried was this. Suppose that by some system of numerical substitution each of these numbers represents a letter. Then groups of these letters together with the letters already in the circles should represent words. Of course it is difficult to group them, though we tried again and again. At first the idea seemed promising, but we could make nothing of it. We couldn’t find any system either of substitution or of grouping which would give a glimmering of sense. No, we’re up against it and no mistake, and when we think of the issues involved we go nearly mad from exasperation. Take the thing, Mr. Cheyne, and see what you and Miss Merrill can do. That is the original, but I have made a tracing of it, so that we can continue our work simultaneously.”