He was wrong in taking counsel with his auxiliaries in the full light of the moon in the Carrefour Rollin.Advice is certainly useful；it is a good thing to know and to interrogate those of the dogs who deserve confidence；but the hunter cannot be too cautious when he is chasing uneasy animals like the wolf and the convict.
Javert，by taking too much thought as to how he should set the bloodhounds of the pack on the trail，alarmed the beast by giving him wind of the dart，and so made him run.Above all，he was wrong in that after he had picked up the scent again on the bridge of Austerlitz，he played that formidable and puerile game of keeping such a man at the end of a thread.He thought himself stronger than he was，and believed that he could play at the game of the mouse and the lion.
At the same time，he reckoned himself as too weak，when he judged it necessary to obtain reinforcement.
Fatal precaution，waste of precious time！Javert committed all these blunders，and none the less was one of the cleverest and most correct spies that ever existed.
He was，in the full force of the term，what is called in venery a knowing dog.But what is there that is perfect？
Great strategists have their eclipses.
The greatest follies are often composed，like the largest ropes，of a multitude of strands.
Take the cable thread by thread，take all the petty determining motives separately，and you can break them one after the other，and you say，'That is all there is of it！'Braid them，twist them together；the result is enormous：
it is Attila hesitating between Marcian on the east and Valentinian on the west；it is Hannibal tarrying at Capua；it is Danton falling asleep at Arcis-sur-Aube.
However that may be，even at the moment when he saw that Jean Valjean had escaped him，Javert did not lose his head.Sure that the convict who had broken his ban could not be far off，he established sentinels，he organized traps and ambuscades，and beat the quarter all that night.
The first thing he saw was the disorder in the street lantern whose rope had been cut.A precious sign which，however，led him astray，since it caused him to turn all his researches in the direction of the Cul-de-Sac Genrot.In this blind alley there were tolerably low walls which abutted on gardens whose bounds adjoined the immense stretches of waste land.Jean Valjean evidently must have fled in that direction.
The fact is，that had he penetrated a little further in the Cul-de-Sac Genrot，he would probably have done so and have been lost.
Javert explored these gardens and these waste stretches as though he had been hunting for a needle.
At daybreak he left two intelligent men on the outlook，and returned to the Prefecture of Police，as much ashamed as a police spy who had been captured by a robber might have been.
BOOK SIXTH.——LE PETIT-PICPUS
Ⅰ NUMBER 62 RUE PETIT-PICPUS
Nothing，half a century ago，more resembled every other carriage gate than the carriage gate of Number 62 Rue Petit-Picpus.This entrance，which usually stood ajar in the most inviting fashion，permitted a view of two things，neither of which have anything very funereal about them，——a courtyard surrounded by walls hung with vines，and the face of a lounging porter.
Above the wall，at the bottom of the court，tall trees were visible.
When a ray of sunlight enlivened the courtyard，when a glass of wine cheered up the porter，it was difficult to pass Number 62 Little Picpus Street without carrying away a smiling impression of it.
Nevertheless，it was a sombre place of which one had had a glimpse.
The threshold smiled；the house prayed and wept.
If one succeeded in passing the porter，which was not easy，——which was even nearly impossible for every one，for there was an open sesame！which it was necessary to know，——if，the porter once passed，one entered a little vestibule on the right，on which opened a staircase shut in between two walls and so narrow that only one person could ascend it at a time，if one did not allow one's self to be alarmed by a daubing of canary yellow，with a dado of chocolate which clothed this staircase，if one ventured to ascend it，one crossed a first landing，then a second，and arrived on the first story at a corridor where the yellow wash and the chocolate-hued plinth pursued one with a peaceable persistency.Staircase and corridor were lighted by two beautiful windows.The corridor took a turn and became dark.
If one doubled this cape，one arrived a few paces further on，in front of a door which was all the more mysterious because it was not fastened.
If one opened it，one found one's self in a little chamber about six feet square，tiled，well-scrubbed，clean，cold，and hung with nankin paper with green flowers，at fifteen sous the roll.
A white，dull light fell from a large window，with tiny panes，on the left，which usurped the whole width of the room.
One gazed about，but saw no one；one listened，one heard neither a footstep nor a human murmur.The walls were bare，the chamber was not furnished；there was not even a chair.
One looked again，and beheld on the wall facing the door a quadrangular hole，about a foot square，with a grating of interlacing iron bars，black，knotted，solid，which formed squares——I had almost said meshes——of less than an inch and a half in diagonal length.
The little green flowers of the nankin paper ran in a calm and orderly manner to those iron bars，without being startled or thrown into confusion by their funereal contact.Supposing that a living being had been so wonderfully thin as to essay an entrance or an exit through the square hole，this grating would have prevented it.
It did not allow the passage of the body，but it did allow the passage of the eyes；that is to say，of the mind.This seems to have occurred to them，for it had been re-enforced by a sheet of tin inserted in the wall a little in the rear，and pierced with a thousand holes more microscopic than the holes of a strainer.
At the bottom of this plate，an aperture had been pierced exactly similar to the orifice of a letter box.