"But not just absolutely impossible." "No," said Carrington, still very thoughtfully, "not impossible." "Sir Reginald might never have seen it was a stranger till the man was fairly inside." Carrington smiled and shook his head. "Thin, Bisset; very thin. Why need the man have been a stranger at all?" Bisset's face fell. "But surely you're not believing yon story that it was Sir Malcolm and Miss Farmond after a'?" His visitor stood absolutely silent for a full minute. Then he seemed suddenly to banish the line of thought he was following. "Is it quite certain that those two are engaged?" he asked. Bisset's face showed his surprise at the question. "They all say so," said he. "Have either of them admitted it?" "No, sir." "Why don't they acknowledge it now and get married?" "They say it's because they daurna for fear of the scandal." "'They' say again!" commented Carrington. "But, look here, Bisset, you have been in the house all the time. Did you think they were engaged?" "Honestly, sir, I did not. There's nae doubt Sir Malcolm was sweet on the young lady, but deil a sign of sweetness on him did I ever see in her!" "Do they correspond now?" Bisset shook his head. "Hardly at a'. But of course folks just say they are feared to now." "Has anybody asked either of them if they are--or ever were--engaged?" "No, sir. But if they denied it now, folks would just say the same thing." "Yes. I see--naturally. Lady Cromarty believes it and is keeping Miss Farmond under her eye, the gossips tell me. Is that so?" "Oh, that's true right enough, sir." "Who told Lady Cromarty?" "That I do not know, sir." Again the visitor seemed to be thinking, and again to cast his thoughts aside and take up a new aspect of the case. "Supposing," he suggested, "we were to draw the curtains and light these candles for a few minutes? It might help us to realise the whole thing." This suggestion pleased Mr. Bisset greatly and in a minute or two the candles were lit and the curtains drawn. "Put the table where it stood," said Carrington. "Now which was Sir Reginald's chair? This?" He sat in it and looked slowly round the darkened, candle-lit library. "Now," said he, "suppose I was Sir Reginald, and there came a tap at that window, what would I do?" "If you were the master, sir, you'd go straight to the windie to see who it was." "I wouldn't get in a funk and ring the bell?" "No fears!" said Bisset confidently. "And any one who knew Sir Reginald at all well could count on his not giving the alarm then if they tapped at the window?" "They could that." Carrington looked attentively towards the window. "Those curtains hang close against the window, I see," he observed. "A very slight gap in them would enable any one to get a good view of the room, if the blinds were not down. Were the blinds down that night?" Bisset slapped his knee.