“Your hypothesis?” I said. “Then you really have a theory which is entirely different from mine?”
“Not entirely different, Knox, merely not so comprehensive. I have contented myself thus far with a negative theory, if I may so express it.”
“Negative theory?”
“Exactly. We are dealing, my dear fellow, with a case of bewildering intricacies. For the moment I have focussed upon one feature only.”
“What is that?”
“Upon proving that Colin Camber did not do the murder.”
“Did not do it?”
“Precisely, Knox. Respecting the person or persons who did do it, I had preserved a moderately open mind, up to the moment that Inspector Aylesbury entered the library with the Lee-Enfield.”
“And then?” I said, eagerly.
“Then,” he replied, “I began to think hard. However, since I practise what I preach, or endeavour to do so, I must not permit myself to speculate upon this aspect of the matter until I have tested my theory of Camber’s innocence.”
“In other words,” I said, bitterly, “although you encouraged me to unfold my ideas regarding Mrs. Camber, you were merely laughing at me all the time!”
“My dear Knox!” exclaimed Harley, jumping up impulsively, “please don’t be unjust. Is it like me? On the contrary, Knox”—he looked me squarely in the eyes—“you have given me a platform on which already I have begun to erect one corner of a theory of the crime. Without new facts I can go no further. But this much at least you have done.”
