delicate microphonereceiver. With telephones at their ears they listened intently. Not aword would be uttered in the room without their knowledge. They couldsee nothing, but if anything was whispered they would certainly hear it.

  The minutes dragged slowly past until just before three o'clock a slightsound caught Jules' attention. Some one had entered the room. A momentlater came the rasp of a match being struck.

  Three o'clock boomed from a distant church dock. Footsteps echoedinside. The meeting was assembling!

  How they longed to see into that room of mystery! But that wasimpossible; they must rely upon the microphone alone for all theinformation they could obtain. Jules' hand sought Yvette's wrist, andin the Morse code he tapped out with his fingers--he dared not speak--acaution to listen acutely. Their only hope of identifying the criminalswas by their voices.

  They could see nothing. They could not even tell how many people therewere in the room. But the mutter of conversation in varying tones camedearly to their ears. It consisted mainly, as they expected, of fiercedenunciation of Monsieur le Prefet of Police, whom they named "theAssassin."

  Soon it became clear that the meeting had been called solely to settlethe time and place of the attack; evidently the method had been decidedupon earlier. Not a single word could the listeners catch of how theattack was to be carried out, whether by bomb, or bullet, or knife.Little did they guess the secret and deadly swiftness of the anarchists'plan.

  For some time the discussion continued. Place after place was suggestedand rejected upon one ground or another.

  Suddenly a hard masterful voice cut across the talking.

  "The Place d'Italie will be the best," it declared. "Half the road isup there and the procession must go along the Avenue des Gobelins, closeto the old villa. At that distance it will be impossible to miss. Andthere will be no noise and no fuss till the job is done."

  The Old Villa! Jules knew the place well--an ancient building datingback to Louis XV, solidly built, and with all the quaint architecturalfeatures of the time. Quite unsuitable for any modern purposes, itsvast apartments had by degrees been turned into a queer medley of roomswhich served partly as flats and partly as offices to a heterogeneousmass of tenants, many of them of more than doubtful reputation. But howany attack on Raoul Gregoire could be projected from a building which itwas certain would, on the day of the procession, be packed withsightseers, Jules was at a loss to conceive.

  That, however, remained to be discovered. For the moment the importantthing was to capture the band of conspirators before they could maketheir escape.

  Jules withdrew, and adjusting his portable instrument--a marvel ofcompactness--placed his foot against an iron lamp-post to make an earthcontact, and swiftly called the Prefecture of Police by Morse.

  The telephones were on his ears, and almost next second he heard theanswering signal. Then he tapped out on his wireless transmitter anurgent message. A moment later he and Yvette had slipped clear of theplace, and ran swiftly away. It was no part of their plan to riskrecognition by any of the prisoners.

  At the head of the alley they waited for about six or seven minutes,when they met Roquet, the inspector of the Surete, who was in charge ofthe detectives who were rapidly converging on the inn. To him Julesbriefly explained the situation.

  "We have them safely enough," declared Roquet with a strong accent ofthe Midi. "Every approach has been guarded for the last hour, and noone has been allowed to pass in or out. You can now leave it to us,m'sieur."

  Yvette and Jules were glad enough to say _au revoir_ and to hurry homefor a much-needed rest. They could examine the prisoners at theirleisure at the Prefecture and, if possible, identify them by theirvoices.

  But a startling surprise awaited the detectives.

  Their imperious knocking at the door of the frowsy Chat Mort at firstbrought no reply. A few minutes later the proprietor appeared,half-dressed and yawning drowsily as though just awakened from profoundsleep. He was instantly arrested and handcuffed and the police pouredinto the house, revolvers drawn and ready for what they expected wouldbe a furious combat with reckless and desperate men.

  To their utter amazement the house was empty!

  The room looking on to the courtyard, in which, according to Jules andYvette, the conspirators had held their meeting, was in perfect order,apparently as it had been left the night before when the place was shutup. There was not a sign that anyone had been there for hours, not evena whiff of fresh tobacco smoke to suggest that the room had beenrecently occupied.

  Roquet was utterly mystified. He had, with very good reason, dreamedany escape impossible. Could Jules and Yvette have been mistaken?

  That, he felt, was out of the question. None the less the problemremained--where were the men? The house was speedily searched fromattic to cellars, but in vain. There was not the smallest indicationthat any meeting had been held there!

  Roquet naturally felt intensely foolish, and his embarrassment was in noway lessened by the voluble protestations of the proprietor whodemanded, with every show of righteous indignation, the reason of whathe was pleased to term "an outrageous domiciliary visit." There was, ofcourse, no charge against him, and ultimately the baffled police werecompelled to release him and retire, furious and puzzled at the utterfailure of what had promised to be a brilliant _coup_.

  Three days later the mystery was solved.

  From the cellar of the "Chat Mort" a narrow tunnel had been driven to anequally disreputable establishment a short distance away, and when thepolice had raided the house the plotters had swiftly bolted, leaving theinnkeeper to drop behind them the stone slab in the cellar floor whichcovered the entrance to the tunnel.

  The position now was grave enough, and Yvette, Jules, and Dick discussedit at length with the Prefet and his lieutenants. To all entreatiesthat he should stay out of the procession the Chief resolutely turned adeaf ear, and they found it impossible to shake his resolve.

  Would the conspirators stick to the arrangement made at the "Chat Mort,"or would they, alarmed by the raid on the house, make an eleventh-hourchange in their plans? That was the problem to be solved.

  Monsieur le Prefet was living on the edge of a volcano, and all hisprecautions would, he feared, be of no avail against them.

  Dick felt convinced they would carry out the plan arranged. It couldnot be imagined, he argued, that they would dream they had beenoverheard, and it was evident that the plan had been very carefullyconsidered. Ultimately it was decided to relax none of the ordinaryprecautions, but to keep a specially close watch on the old villa in thePlace d'Italie. Dick decided that, whatever the police did, he wouldmake his own arrangements for that purpose. The sequel proved that itwas well he did so.

  On the night prior to the procession the police carried out a verydrastic _coup_. Every known anarchist in Paris was arrested on somepretext or another and locked up. One by one they were brieflyinterrogated, while Jules and Yvette, concealed in the room behind ascreen, tried to recognise any of the voices they had heard in the ChatMort.

  Fifty or sixty prisoners had been interviewed before Jules and hissister standing behind a screen heard a voice they recognised. It wasthat of the man who had suggested the old villa in the Place d'Italie asa suitable base for the attempt on the Prefet. None of the others couldbe identified, and it was evident that the worst of the miscreants werestill at large.

  The man whom they recognised proved to be Anton Kapok, a Hungarian ofwhom nothing was known except that he was in the habit of deliveringviolent harangues at Socialist and Anarchist meetings. But it wasevident now that he was far more dangerous than the police had hithertosupposed.

  Closely interrogated, he denied everything. He knew nothing, hedeclared, of the "Chat Mort" and had not been mixed up in anyconspiracy. His Anarchist proclivities, however, he boldly admitted anddeclared that the police knew all there was to know about him.

  To the police a search of Kapok's room in Bellville revealed
nothingmore incriminating than a mass of Anarchist literature. But Dick made adiscovery which they had overlooked.

  Close to the ceiling, immediately above the fireplace, was suspended ontwo hooks what looked like a rod from which pictures might be hung. Thepolice had, in fact, so regarded it. Dick never knew what aroused hissuspicions, but something impelled him to mount a ladder and fetch therod down. Then he made a startling discovery.

  The supposed rod was nothing less than one of the wonderful blow-pipesused by some of the aboriginal tribes of South America and elsewhere toshoot their poisoned darts with which they either fought their enemiesor killed dangerous animals. One of the darts, a tiny affair fashionedout of a sharp thorn with a tuft of cotton which just filled the tube,was actually in position.

  Instantly Dick's mind travelled back to the strange deaths nearly a yearbefore of two police officials who had been specially astute in theanti-anarchist campaign. Both had been found