At the moment that Tournefort first caught sight of him he appeared uncertain of his way. Then for a while he watched Tournefort, who was coming at a sharp trot towards him. Finally, he seemed to make up his mind very suddenly and, giving a last, quick look round, he walked rapidly along the upper road. Tournefort drew rein, waiting for his colleagues to come up with him. Then he told them what he had seen.

"It is Rateau, sure enough," he said. "I saw his face quite distinctly and heard his abominable cough. he is trying to get into Paris. That road leads nowhere but to the barrier. There, of course, he will be stopped, and-"

The other two had also brought their horses to a halt. The situation had become tense, and a plan for future action had at once to be decided on. Already Chauvelin, masterful and sure of himself, had assumed command of the little party. Now he broke in abruptly on Tournefort's vapid reflections.

We don't want him stopped at the barrier," he said in his usual curt, authoritative manner. "You, citizen Tournefort," he continued, "will ride as fast as you can to get to the gate, making a détour by the lower road. You will immediately demand to speak with the sergeant who is in command, and you will give him a detailed description of the man Rateau. Then you will tell him in my name that, should such a man present himself at the gate, he must be allowed to enter the city unmolested."

Gourdon gave a quick cry of protest.

"Let the man go unmolested? Citizen Chauvelin, think what you are doing!"

"I always think of what I am doing," retorted Chauvelin curtly, "and have no need of outside guidance in the process." Then he turned once more to Tournefort. "You yourself, citizen," he continued, in sharp, decisive tones which admitted of no argument, "will dismount as soon as you are inside the city. You will keep the gate under observation. The moment you see the man Rateau, you will shadow him, and on no account lose sight of him. Understand?"

"You may trust me, citizen Chauvelin," Tournefort replied, elated at the prospect of work which was so entirely congenial to him. "But will you tell me-"

"I will tell you this much, citizen Tournefort," broke in Chauvelin with some acerbity, "that though we have traced the diamonds and the thief so far, we have, through your folly last night, lost complete track of the ci-devant Comtesse de Sucy and of the man Bertin. We want Rateau to show us where they are."

"I understand," murmured the other meekly.

"That's a mercy!" riposted Chauvelin dryly. "Then quickly, man. Lose no time! Try to get a few minutes advance on Rateau; then slip into the guard-room to change into less conspicuous clothes. Citizen Gourdon and I will continue on the upper road and keep the man in sight in case he should think of altering his course. In any event, we'll met you just inside the barrier. But it, in the meanwhile, you have to get on Rateau's track before we have arrived on the scene, leave the usual indications as to the direction which you have taken."

Having given his orders and satisfied himself that they were fully understood, he gave a curt command, "En avant," and once more the three of them rode at a sharp trot down the road towards the city.

Chapter IV:

Citizen Rateau, if he though about the matter at all, must indeed have been vastly surprised at the unwonted amiability or indifference of Sergeant Ribot, who was in command at the gate of Gentilly. Ribot only threw a very perfunctory glance at the greasy permit which Rateau presented to him, and when he put the usual query, "What's in that parcel?" and Rateau gave the reply: "Two heads of cabbage and a bunch of carrots," Ribot merely poked one of his fingers into the bundle, felt that a cabbage leaf did effectually lie on top, and thereupon gave the formal order: "Pass on, citizen, in the name of the Republic!" without any hesitation.

Tournefort, who had watched the brief little incident from behind the window of a neighbouring cabaret, could not help but chuckle to himself. Never had he seen game walk more readily into a trap. Rateau, after he had passed the barrier, appeared undecided which way he would go. He looked with obvious longing towards the cabaret, behind which the keenest agent on the staff of the Committee of Public Safety was even now esconced. But seemingly a halt within those hospitable doors did not form part of his programme, and a moment or two later he turned sharply on his heel and strode rapidly down the Rue de l'Oursine.

Tournefort allowed him a fair start, and then made ready to follow.

Just as he was stepping out of the cabaret he spied Chauvelin and Gourdon coming through the gates. They, too, had apparently made a brief halt inside the guard-room, where - as at most of the gates - a store of various disguises was always kept ready for the use of the numerous sleuth-hounds employed by the Committee of Public Safety. Here the two men had exchanged their official garments for suits of sombre cloth, which gave them the appearance of a couple of humble bourgeois going quietly about their business. Tournefort had donned an old blouse, tattered stockings, and shoes down at hell. With his hands buried in his breeches pockets, he, too, turned into the long narrow Rue de l'Oursine, which after a sharp curve abuts on the Rue Mouffetard.

Rateau was walking rapidly, taking big strides with his long legs. Tournefort, now sauntering in the gutter in the middle of the road, now darting in and out of open doorways, kept his quarry well in sight. Chauvelin and Gourdon lagged some little way behind. It was still raining, but not heavily - a thin drizzle, which penetrated almost to the marrow. Not many passers-by haunted this forlon quarter of old Paris. To right and left tall houses almost obscured the last quickly fading light of the grey September day.

At the bottom of the Rue Mouffetard, Rateau came once more to a halt. A network of narrow streets radiated from this centre. He looked all round him and also behind. It was difficult to know whether he had a sudden suspicion that he was being followed; certain it is that, after a very brief moment of hesitation, he plunged suddenly into the narrow Rue Contrescarpe and disappeared from view.

Tournefort was after him in a trice. When he reached the corner of the street he saw Rateau, at the farther end of it, take a sudden sharp turn to the right. But not before he had very obviously spied his pursuer, for at that moment his entire demeanour changed. An air of furtive anxiety was expressed in his whole attitude. Even at that distance Tournefort could see him clutching his bulky parcel close to his chest.

After that the pursuit became closer and hotter. Rateau was in and out of that tight network of streets which cluster around the Place de Fourci, intent, apparently, on throwing his pursuers off the scent, for after a while he was running round and round in a circle. Now up the Rue des Poules, then to the right and to the right again; back in the Place de Fourci. Then straight across it once more to the Rue Contrescarpe, where he presently disappeared so completely from view that Tournefort thought that the earth must have swallowed him up.

Tournefort was a man capable of great physical exertion. His calling often made heavy demands upon his powers of endurance; but never before had he grappled with so strenuous a task. Puffing and panting, now running at top speed, anon brought to a halt by the doubling-up tactics of his quarry, his great difficulty was the fact that citizen Chauvelin did not wish the man Rateau to be apprehended; did not wish him to know that he was being pursued. And Tournefort had need of all his wits to keep well under the shadow of any projecting wall or under cover of open doorways which were conveniently in the way, and all the while not to lose sight of that consumptive giant, who seemed to be playing some intricate game which well-nigh exhausted the strength of citizen Tournefort.