'I see,' said Chippy. 'Well, I've done the boot up again. Now we'll have a look round for that sergeant. We've come straight back to the part where we seed 'im afore.' 'So we have,' said Dick; 'there's Woody Knap right in front of us again.' 'Hello! wot's that?' cried Chippy, whose eyes were always on the move. He was pointing through the covert towards the direction from which they had come. Something was moving in the distant gorse, and then they saw the spy. He was hobbling along at a good speed, his eyes bent on the ground. 'Here he comes again!' cried Dick, 'and, by Jingo, he's following our trail. I say, Chippy, he can do a bit of scouting, too.' 'That's a fact,' said Chippy, and began to steal out of the covert on the farther side. Before leaving it the two boys paused for a last look at the spy. His wounded foot was bound up in his cap with a handkerchief round it, and he was covering the ground at considerable speed. He was a first-rate tracker, and he was coming along their trail as easily as if he had been trotting on a plain road. For a few seconds the boys were held fascinated by the sight of this savage sleuth-hound at their heels. They were held as the rabbit is held, when he pauses in his flight, yet knows that all the time the weasel is following swiftly in quest of his life. Suddenly the boys started, looked at each other, threw off the feeling, and ran away at their best speed, for the halt had given them their wind again. 'Good job we 'ad a place where we could see 'im a-comin',' remarked Chippy. 'I ain't a-goin' to forget that tip.' 'He sees us now,' cried Dick. 'He's coming faster.' The boys were no longer hidden by the covert in which they had halted. They had come into the spy's field of view, and now he pursued by sight, and leapt out at the best speed he could make. Chippy looked round. 'Droppin' 'is foot down a bit tender,' commented the Raven; 'we can choke 'im off any time we want on a rough patch.' Dick now pulled out his patrol whistle, and began to blow it. 'I'll join yer,' said Chippy, and pulled out his. The two whistles sent their shrill blasts far over the heath, as the boys ran on and on, and the spy still pursued. The latter had faltered for a moment when the whistles rang out but he had recovered his speed and hastened forward. He thought that it was a trick, that the boys wished him to fear that they had support near at hand. If only he could seize the boy who carried his boot! That was his great hope. CHAPTER XVI THE SPY IS SEIZED