On another occasion I was Orderly Officer of the Day at Aire, and "visiting rounds" late at night, a sentry on duty in the town, belonging to a Scottish regiment, told me that he had a man dressed in officer’s uniform under observation, who aroused his suspicion owing to the questions addressed to him as to the whereabouts of certain brigades and regiments. He had already, he said, reported the matter to his corporal, who had posted two sentries outside the house into which the suspect had gone. My duty was quite plain: this case was one for immediate investigation; so, accompanied by the sentry, I went up to the house, which was only a few yards away, and which happened to be a _brasserie_. The next thing to be done was to gain admittance to the _brasserie_. It was now after midnight. Having given the sentries orders to load their rifles, but only to loose off in the event of their suspect endeavouring to make his escape or resist escort, and to shoot low at that, with my revolver in one hand I rang the _brasserie_ bell with the other. It was one of those large bells suspended at some height, actuated by a long chain, and which have a way of continuing to ring for some time after the chain has been pulled. Very soon, up went a window on the first floor, and out of it appeared the head and shoulders of a woman, obviously aroused from her slumbers. I inquired in the best French I could command if there was an "Officier anglais" billeted in the house. She replied that there was one, and she would go to his room and wake him. In a few minutes, after much clanking of chains and bolts, the front door was opened. This, then, was the critical moment! A Captain of the —— Regiment emerged and asked what the —— I wanted and why the —— I had woke him up at such an unearthly hour of the night. The sentry had made a mistake in his overzealousness. The alleged spy was an officer, who had that night returned from leave, and finding no one about except a sentry, had sought from him such information as to the whereabouts of his unit as would enable him to rejoin it on the following morning. So, apologizing profusely and explaining my position in the matter, I withdrew, greatly disappointed at being denied the excitement of catching a real spy.