“Taking with me a long, thin rope which I had in my room, anticipating such a trial for it, I roused five of my picked men, and silently we made our way to the foot of the northern cliff. Here, with the rope around my waist, I worked my way diagonally up along a cleft in the rock, which, like others parallel to it, marked the face of the precipice. A slip would be fatal. The loosening of a stone would give warning to the sentinel, whose slow steps I heard on the wall above me, but at last I reached a narrow ledge without accident, and standing up in the darkness, my chin was level with the top of the wall on which the sentry paced. The shelf between the bottom of the wall and the top of the cliff was perhaps three feet in width, and gave ample room for a man careful of his footing. Aided by the rope, the others, less expert climbers than myself, made their way to my side one by one, and the six of us stood on the ledge under the low wall. We were all in our stockinged feet, some of the men, in fact, not even having stockings on. As the sentinel passed, we crouching in the darkness under the wall, the most agile of our party sprang up behind him. The soldier had taken off his jacket, and tip-toeing behind the sentinel, he threw the garment over his head, tightening it with a twist that almost strangled the man. Then seizing his gun so that it would not clatter on the stones, held him thus helpless while we five climbed up beside him. Feeling under the jacket, I put my right hand firmly on the sentinel’s throat, and nearly choking the breath out of him, said:-- “‘Your life depends on your actions now. Will you utter a sound if I let go your throat?’ “The man shook his head vehemently, and I released my clutch. “‘Now,’ I said to him, ‘where is the powder stored? Answer in a whisper, and speak truly.’ “‘The bulk of the powder,’ he answered, ‘is in the vault below the citadel.’ “‘Where is the rest of it?’ I whispered. “‘In the lower room of the round tower by the gate.’ “‘Nonsense,’ I said: ‘they would never store it in a place so liable to attack.’ “‘There was nowhere else to put it,’ replied the sentinel, ‘unless they left it in the open courtyard, which would be quite as unsafe.’ “‘Is the door to the lower room in the tower bolted?’ “‘There is no door,’ replied the sentry, ‘but a low archway. This archway has not been closed, because no cannon-balls ever come from the northern side.’ “‘How much powder is there in this room?’ “‘I do not know; nine or ten barrels, I think.’