At that moment the clouds cleared away from the moon and clearly revealed the intruder. He was one of the Macfies, Singleton could see, and fully armed. He dismounted at the border of the wood, and advanced cautiously on foot to the edge of the moat. This he made no attempt to cross, but made his observations from the far side. Singleton, taking care not to be seen, crept back into the armoury, from which he took a bugle. Bringing it out into the terrace, he sounded a few shrill notes; and then instantly seizing a lantern, ran hurriedly to and fro with it on various parts of the battlements. Then without waiting a moment he took up a musket and fired it in the direction of the scout, who, however, was by this time out of reach. "There!" said Singleton, putting down his weapon; "that will satisfy them we are on the alert, all of us, and ready for them! Perhaps they will think better of it, and turn tail." No! in a few minutes the sound of the advancing troop again rose in the night. They came on at a trot, dragging their gun along with them. Presently there was a gleam among the trees, and next moment some fifty horsemen appeared in view, with a cannon in their midst, which, equally to Singleton's satisfaction and surprise, they proceeded to get into position at the very entrance to the wood. It was on this spot, it will be remembered, that the young laird had carefully levelled the gun that surmounted the great gate. Everything depended now on the skill with which he had aimed it. He gave the foe a minute or two to fix and point their weapon, and once more carefully calculated the poise of his own. Then, just as they were proceeding to load, and the horsemen were preparing to follow up the attack on the gate, he applied the match, and with a mighty roar the piece discharged. It was an anxious moment while the smoke slowly cleared away. When it did he had the joy of beholding the enemy's gun on end and disabled, and not only it, but at least three of the enemy themselves involved in the same disaster. He could not resist a triumphant cheer at this success, which was promptly answered by a defiant shout from the enraged Macfies as they set spurs to their horses and rushed towards the moat. And now began the hard work of the night. For the foe thought nothing of such a narrow obstacle as a simple ditch. Some swam it on horseback, and some left their animals behind, but all--all except two whom Singleton's trusty muskets had found out--crossed in safety. The raid they made on the great gate was something terrific, and Singleton's heart trembled within him as he heard it creak before their united weight. But he worked away steadily at his post, always taking care not to expose himself, yet never wasting a shot with a bad aim.