“Very well, papa, these tracks explain everything.  When they reached this spot, our fugitives saw the light of an approaching cab, which was returning from the centre of Paris.  It was empty, and proved their salvation.  They waited, and when it came nearer they hailed the driver.  No doubt they promised him a handsome fare; this is indeed evident, since he consented to go back again.  He turned round here; they got into the vehicle, and that is why the footprints go no further.”

This explanation did not please Lecoq’s companion.  “Have we made any great progress now that we know that?” he asked.

Lecoq could not restrain an impulse to shrug his shoulders.  “Did you expect that the tracks made by the fugitives would lead us through Paris and up to their very doors?” he asked.

“No; but—­”

“Then what would you ask more?  Do you think that I shall not know how to find this driver to-morrow?  He was returning with his empty vehicle, his day’s work was ended; hence, his stable is in the neighborhood.  Do you suppose that he will have forgotten that he took up two persons in the Rue du Chevaleret?  He will tell us where he drove them; but that will not do us any good, for, of course, they will not have given him their real address.  But at all events he can probably give us a description of them, tell us how they were dressed, describe their appearance, their manner, and their age.  And with that, and what we already know—­”

An eloquent gesture expressed the remainder of his thought, then he added:  “We must now go back to the Poivriere, and go quickly.  And you, my friend, may now extinguish your lantern.”

While doing his best to keep pace with his companion, who was in such haste to get back to the Poivriere that he almost ran, Father Absinthe’s thoughts were as busy as his legs, and an entirely new train of ideas was awakened in his mind.

During the twenty-five years that he had been connected with the police force, the good man—­to use his own expression—­had seen many of his colleagues walk over him and win, after only a few months’ work, a promotion that his long years of service had not gained for him.  In these cases he had not failed to accuse his superiors of injustice, and his fortunate rivals of gross flattery.  In his opinion, seniority was the only claim to advancement—­the only, the best, the most respectable claim; and he was wont to sum up all his opinions, all his grief and bitterness of mind in one phrase:  “It is infamous to pass over an old member of the service.”

To-night, however, Father Absinthe discovered that there is something else in the world besides seniority, and sufficient reasons for what he had formerly regarded as favoritism.  He secretly confessed that this newcomer whom he had treated so carelessly had just followed up a clue as he, veteran though he was, would never have succeeded in doing.

But communing with himself was not this good man’s forte; he soon grew weary of reflection; and on reaching a place where they were obliged to proceed more slowly on account of the badness of the road, he deemed it a favorable opportunity to resume the conversation.  “You are silent, comrade,” he ventured to remark, “and one might swear that you were not exactly pleased.”