Ember looked at Jane for a moment. Then he looked away. In that moment Jane saw something—she could not really tell what. The nearest that she could get to it was “triumph.” Yes, that was it, triumph. As he looked away he said, very low, “She will have scope enough,” and there was a little tingling silence. He broke it in an utterly unforeseen manner. With an abrupt change of voice he asked: “Ever learn chemistry?” “No,” said Jane, and then wondered whether she was telling the truth about Renata. “’M—know what a formula is?” Jane put a dash of ignorant conviction into her voice: “Oh, I think so—oh yes, of course.” “Well, what is it?” She looked puzzled. “It’s difficult to explain things, isn’t it? Of course I know ‘formulate,’ and er—‘formal.’ But it’s—it’s something learned, isn’t it?” Ember’s sarcastic smile showed for a moment. With a horrid inward qualm Jane wondered whether she had overdone Renata’s ignorance. “A formula is a prescription,” said Ember slowly. “If you remember that, I think you’ll find it all quite simple. So that Formula ‘A’ is simply a prescription for making something up, labelled ‘A’ for convenience’ sake.” Jane let her eyes become quite round. “Is it?” she said in the blankest tone at her command. “But ... but what is Formula ‘A,’ Mr. Ember?” “That, my dear Miss Renata, is what a good many people would like to know.” “Would they? Why?” “They would. In fact, some of them—person or persons unknown—wanted to know so much that they have gone to the length of stealing Formula ‘A.’ That, at least, is Captain March’s opinion, and the reason for his visit here. So I should be careful, very careful indeed, about betraying any knowledge of Formula ‘A.’” Jane whisked round, stared blankly, and said in largest capitals: “ME?” Then, after a pause, she burst out laughing. “What do you mean?” “You either know, or you don’t know,” said Jeffrey Ember. “If you don’t know, I’m not going to tell you. If you do, I have just given you a warning. A very valuable Government secret has been stolen, and if Captain March were to suspect that you were in any way involved—well, I suppose ... I need not tell you that the consequences would be serious beyond words.” Jane gazed at him in a breathless delight which she hoped was not apparent. The day had been singularly lacking in pleasantness, but it was undoubtedly pleasing to receive a solemn warning of the dreadful fate that might overtake her if Henry should suspect that she knew anything about Formula “A.” “But I haven’t the slightest idea what Formula ‘A’ can be,” she said. “It sounds frightfully exciting. Do tell me some more. Was it stolen? And how could anything be stolen here?” “Who frightened you?” he said suddenly. Jane caught her breath.