“Someone is moving in that room,” said Holmes in a whisper, his gaunt and eager face thrust forward to the windowpane. “Yes, I can see his shadow. There he is again! He has a candle in his hand. Now he is peering across. He wants to be sure that she is on the lookout. Now he begins to flash. Take the message also, Watson, that we may check each other. A single flash⁠—that is a , surely. Now, then. How many did you make it? Twenty. So did I. That should mean t . at ⁠—that’s intelligible enough. Another t . Surely this is the beginning of a second word. Now, then⁠— tenta . Dead stop. That can’t be all, Watson? attenta gives no sense. Nor is it any better as three words at , ten