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, waited 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 the gate, making a detour 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 in to 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 meet you just inside the barrier.  But if, 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.”