At last, in short rapid phrases, he acquainted me with things which
   plunged me into a state bordering on complete bewilderment.  Indeed,
   the results of that still unknown science known as hypnotism, for
   example, were not more inexplicable than the disappearance of the
   "matter" of the murderer at the moment when four persons were within
   touch of him.  I speak of hypnotism as I would of electricity, for
   of the nature of both we are ignorant and we know little of their
   laws.  I cite these examples because, at the time, the case appeared
   to me to be only explicable by the inexplicable,--that is to say,
   by an event outside of known natural laws.  And yet, if I had had
   Rouletabille's brain, I should, like him, have had a presentiment
   of the natural explanation; for the most curious thing about all
   the mysteries of the Glandier case was the natural manner in which
   he explained them.
   I have among the papers that were sent me by the young man, after
   the affair was over, a note-book of his, in which a complete account
   is given of the phenomenon of the disappearance of the "matter" of
   the assassin, and the thoughts to which it gave rise in the mind of
   my young friend.  It is preferable, I think, to give the reader this
   account, rather than continue to reproduce my conversation with
   Rouletabille; for I should be afraid, in a history of this nature,
   to add a word that was not in accordance with the strictest truth.
   CHAPTER XV
   The Trap
   (EXTRACT FROM THE NOTE-BOOK OF JOSEPH ROULETABILLE)
   "Last night--the night between the 29th and 30th of October--" wrote
   Joseph Rouletabille, "I woke up towards one o'clock in the morning.
   Was it sleeplessness, or noise without?--The cry of the Bete du
   Bon Dieu rang out with sinister loudness from the end of the park.
   I rose and opened the window.  Cold wind and rain; opaque darkness;
   silence.  I reclosed my window.  Again the sound of the cat's weird
   cry in the distance.  I partly dressed in haste.  The weather was
   too bad for even a cat to be turned out in it.  What did it mean,
   then--that imitating of the mewing of Mother Angenoux' cat so near
   the chateau?  I seized a good-sized stick, the only weapon I had,
   and, without making any noise, opened the door.
   "The gallery into which I went was well lit by a lamp with a
   reflector.  I felt a keen current of air and, on turning, found the
   window open, at the extreme end of the gallery, which I call the
   'off-turning' gallery, to distinguish it from the 'right' gallery,
   on to which the apartment of Mademoiselle Stangerson opened.  These
   two galleries cross each other at right angles.  Who had left that
   window open?  Or, who had come to open it?  I went to the window and
   leaned out.  Five feet below me there was a sort of terrace over the
   semi-circular projection of a room on the ground-floor.  One could,
   if one wanted, jump from the window on to the terrace, and allow
   oneself to drop from it into the court of the chateau.  Whoever had
   entered by this road had, evidently, not had a key to the vestibule
   door.  But why should I be thinking of my previous night's attempt
   with the ladder?--Because of the open window--left open, perhaps,
   by the negligence of a servant?  I reclosed it, smiling at the ease
   with which I built a drama on the mere suggestion of an open window.
   "Again the cry of the Bete du Bon Dieu!--and then silence.  The
   rain ceased to beat on the window.  All in the chateau slept.  I
   walked with infinite precaution on the carpet of the gallery.  On
   reaching the corner of the 'right' gallery, I peered round it
   cautiously.  There was another lamp there with a reflector which
   quite lit up the several objects in it,--three chairs and some
   pictures hanging on the wall.  What was I doing there?  Perfect
   silence reigned throughout.  Everything was sunk in repose.  What
   was the instinct that urged me towards Mademoiselle Stangerson's
   chamber?  Why did a voice within me cry: 'Go on, to the chamber of
   Mademoiselle Stangerson!'  I cast my eyes down upon the carpet on
   which I was treading and saw that my steps were being directed
   towards Mademoiselle Stangerson's chamber by the marks of steps
   that had already been made there.  Yes, on the carpet were traces
   of footsteps stained with mud leading to the chamber of Mademoiselle
   Stangerson.  Horror!  Horror!--I recognised in those footprints
   the impression of the neat boots of the murderer!  He had come, then,
   from without in this wretched night.  If you could descend from the
   gallery by way of the window, by means of the terrace, then you could
   get into the chateau by the same means.
   "The murderer was still in the chateau, for here were marks as of
   returning footsteps.  He had entered by the open window at the
   extremity of the 'off-turning' gallery; he had passed Frederic
   Larsan's door and mine, had turned to the right, and had entered
   Mademoiselle Stangerson's room.  I am before the door of her
   ante-room--it is open.  I push it, without making the least noise.
   Under the door of the room itself I see a streak of light.  I
   listen--no sound--not even of breathing!  Ah!--if I only knew
   what was passing in the silence that is behind that door!  I find
   the door locked and the key turned on the inner side.  And the
   murderer is there, perhaps.  He must be there!  Will he escape this
   time?--All depends on me!--I must be calm, and above all, I must
   make no false steps.  I must see into that room.  I can enter it by
   Mademoiselle Stangerson's drawing-room; but, to do that I should
   have to cross her boudoir; and while I am there, the murderer may
   escape by the gallery door--the door in front of which I am now
   standing.
   "I am sure that no other crime is being committed, on this night;
   for there is complete silence in the boudoir, where two nurses are
   taking care of Mademoiselle Stangerson until she is restored to
   health.
   "As I am almost sure that the murderer is there, why do I not at
   once give the alarm?  The murderer may, perhaps, escape; but,
   perhaps, I may be able to save Mademoiselle Stangerson's life.
   Suppose the murderer on this occasion is not here to murder?  The
   door has been opened to allow him to enter; by whom?--And it has
   been refastened--by whom?--Mademoiselle Stangerson shuts herself
   up in her apartment with her nurses every night.  Who turned the
   key of that chamber to allow the murderer to enter?--The nurses,
   --two faithful domestics?  The old chambermaid, Sylvia?  It is very
   improbable.  Besides, they slept in the boudoir, and Mademoiselle
   Stangerson, very nervous and careful, Monsieur Robert Darzac told
   me, sees to her own safety since she has been well enough to move
   about in her room, which I have not yet seen her leave.  This
   nervousness and sudden care on her part, which had struck Monsieur
   Darzac, had given me, also, food for thought.  At the time of the
   crime in The Yellow Room, there can be no doubt that she expected
   the murderer.  Was he expected this night?--Was it she herself 
					     					 			
   who had opened her door to him?  Had she some reason for doing so?
   Was she obliged to do it?--Was it a meeting for purposes of crime?
   --Certainly it was not a lover's meeting, for I believe Mademoiselle
   Stangerson adores Monsieur Darzac.
   "All these reflections ran through my brain like a flash of
   lightning.  What would I not give to know!
   "It is possible that there was some reason for the awful silence.
   My intervention might do more harm than good.  How could I tell?
   How could I know I might not any moment cause another crime?  If
   I could only see and know, without breaking that silence!
   "I left the ante-room and descended the central stairs to the
   vestibule and, as silently as possible, made my way to the little
   room on the ground-floor where Daddy Jacques had been sleeping since
   the attack made at the pavilion.
   "I found him dressed, his eyes wide open, almost haggard.  He did
   not seem surprised to see me.  He told me that he had got up because
   he had heard the cry of the Bete du bon Dieu, and because he had
   heard footsteps in the park, close to his window, out of which he
   had looked and, just then, had seen a black shadow pass by.  I asked
   him whether he had a firearm of any kind.  No, he no longer kept
   one, since the examining magistrate had taken his revolver from him.
   We went out together, by a little back door, into the park, and
   stole along the chateau to the point which is just below Mademoiselle
   Stangerson's window.
   "I placed Daddy Jacques against the wall, ordering him not to stir
   from the spot, while I, taking advantage of a moment when the moon
   was hidden by a cloud, moved to the front of the window, out of the
   patch of light which came from it,--for the window was half-open!
   If I could only know what was passing in that silent chamber!  I
   returned to Daddy Jacques and whispered the word 'ladder' in his ear.
   At first I had thought of the tree which, a week ago, served me for
   an observatory; but I immediately saw that, from the way the window
   was half-opened, I should not be able to see from that point of view
   anything that was passing in the room; and I wanted, not only to see,
   but to hear, and--to act.
   "Greatly agitated, almost trembling, Daddy Jacques disappeared for
   a moment and returned without the ladder, but making signs to me
   with his arms, as signals to me to come quickly to him.  When I got
   near him he gasped: 'Come!'
   "'I went to the donjon in search of my ladder, and in the lower part
   of the donjon which serves me and the gardener for a lumber room, I
   found the door open and the ladder gone.  On coming out, that's what
   I caught sight of by the light of the moon.
   "And he pointed to the further end of the chateau, where a ladder
   stood resting against the stone brackets supporting the terrace,
   under the window which I had found open.  The projection of the
   terrace had prevented my seeing it.  Thanks to that ladder, it was
   quite easy to get into the 'off-turning' gallery of the first floor,
   and I had no doubt of it having been the road taken by the unknown.
   "We ran to the ladder, but at the moment of reaching it, Daddy
   Jacques drew my attention to the half-open door of the little
   semi-circular room, situated under the terrace, at the extremity of
   the right wing of the chateau, having the terrace for its roof.
   Daddy Jacques pushed the door open a little further and looked in.
   "'He's not there!" he whispered.
   "Who is not there?"
   "The forest--keeper."
   With his lips once more to my ear, he added:
   "'Do you know that he has slept in the upper room of the donjon ever
   since it was restored?'  And with the same gesture he pointed to the
   half-open door, the ladder, the terrace, and the windows in the
   'off-turning' gallery which, a little while before, I had re-closed.
   "What were my thoughts then?  I had no time to think.  I felt more
   than I thought.
   "Evidently, I felt, if the forest-keeper is up there in the chamber
   (I say, if, because at this moment, apart from the presence of the
   ladder and his vacant room, there are no evidences which permit me
   even to suspect him)--if he is there, he has been obliged to pass
   by the ladder, and the rooms which lie behind his, in his new
   lodging, are occupied by the family of the steward and by the cook,
   and by the kitchens, which bar the way by the vestibule to the
   interior of the chateau.  And if he had been there during the evening
   on any pretext, it would have been easy for him to go into the
   gallery and see that the window could be simply pushed open from
   the outside.  This question of the unfastened window easily narrowed
   the field of search for the murderer.  He must belong to the house,
   unless he had an accomplice, which I do not believe he had; unless
   --unless Mademoiselle Stangerson herself had seen that that window
   was not fastened from the inside.  But, then,--what could be the
   frightful secret which put her under the necessity of doing away
   with obstacles that separated her from the murderer?
   "I seized hold of the ladder, and we returned to the back of the
   chateau to see if the window of the chamber was still half-open.
   The blind was drawn but did not join and allowed a bright stream
   of light to escape and fall upon the path at our feet.  I planted
   the ladder under the window.  I am almost sure that I made no noise;
   and while Daddy Jacques remained at the foot of the ladder, I
   mounted it, very quietly, my stout stick in my hand.  I held my
   breath and lifted my feet with the greatest care.  Suddenly a heavy
   cloud discharged itself at that moment in a fresh downpour of rain.
   "At the same instant the sinister cry of the Bete du bon Dieu
   arrested me in my ascent.  It seemed to me to have come from close
   by me--only a few yards away.  Was the cry a signal?--Had some
   accomplice of the man seen me on the ladder!--Would the cry bring
   the man to the window?--Perhaps!  Ah, there he was at the window!
   I felt his head above me.  I heard the sound of his breath!  I could
   not look up towards him; the least movement of my head, and--I
   might be lost.  Would he see me?--Would he peer into the darkness?
   No; he went away.  He had seen nothing.  I felt, rather than heard,
   him moving on tip-toe in the room; and I mounted a few steps higher.
   My head reached to the level of the window-sill; my forehead rose
   above it; my eyes looked between the opening in the blinds--and I
   saw--A man seated at Mademoiselle Stangerson's little desk,
   writing.  His back was turned toward me.  A candle was lit before
   him, and he bent over the flame, the light from it projecting
   shapeless shadows.  I saw nothing but a monstrous, stooping back.
   "Mademoiselle Stangerson herself was not there!--Her bed had not
   been lain on!  Where, then, was she sleeping that night?  Doubtless
   in the side-room with her women.  Perhaps this was but a guess.  I
   must content myself with the joy of finding the man alone.  I must
   be calm to prepare my trap.
 &nbs 
					     					 			p; "But who, then, is this man writing there before my eyes, seated at
   the desk, as if he were in his own home?  If there had not been that
   ladder under the window; if there had not been those footprints on
   the carpet in the gallery; if there had not been that open window,
   I might have been led to think that this man had a right to be there,
   and that he was there as a matter of course and for reasons about
   which as yet I knew nothing.  But there was no doubt that this
   mysterious unknown was the man of The Yellow Room,--the man to
   whose murderous assault Mademoiselle Stangerson--without denouncing
   him--had had to submit.  If I could but see his face!  Surprise
   and capture him!
   "If I spring into the room at this moment, he will escape by the
   right-hand door opening into the boudoir,--or crossing the
   drawing-room, he will reach the gallery and I shall lose him.  I
   have him now and in five minutes more he'll be safer than if I had
   him in a cage.--What is he doing there, alone in Mademoiselle
   Stangerson's room?--What is he writing?  I descend and place the
   ladder on the ground.  Daddy Jacques follows me.  We re-enter the
   chateau.  I send Daddy Jacques to wake Monsieur Stangerson, and
   instruct him to await my coming in Mademoiselle Stangerson's room
   and to say nothing definite to him before my arrival.  I will go
   and awaken Frederic Larsan.  It's a bore to have to do it, for I
   should have liked to work alone and to have carried off all the
   honors of this affair myself, right under the very nose of the
   sleeping detective.  But Daddy Jacques and Monsieur Stangerson are
   old men, and I am not yet fully developed.  I might not be strong
   enough.  Larsan is used to wrestling and putting on the handcuffs.
   He opened his eyes swollen with sleep, ready to send me flying,
   without in the least believing in my reporter's fancies.  I had to
   assure him that the man was there!
   "'That's strange!' he said; 'I thought I left him this afternoon
   in Paris.'
   "He dressed himself in haste and armed himself with a revolver.  We
   stole quietly into the gallery.
   "'Where is he?' Larsan asked.
   "'In Mademoiselle Stangerson's room.
   "'And--Mademoiselle Stangerson?'
   "'She is not in there.'
   "'Let's go in.'
   "'Don't go there!  On the least alarm the man will escape.  He has
   four ways by which to do it--the door, the window, the boudoir, or
   the room in which the women are sleeping.'
   "'I'll draw him from below.'
   "'And if you fail?--If you only succeed in wounding him--he'll
   escape again, without reckoning that he is certainly armed.  No,
   let me direct the expedition, and I'll answer for everything.'
   "'As you like,' he replied, with fairly good grace.
   "Then, after satisfying myself that all the windows of the two
   galleries were thoroughly secure, I placed Frederic Larsan at the
   end of the 'off-turning' gallery, before the window which I had
   found open and had reclosed.
   "'Under no consideration,' I said to him, 'must you stir from this
   post till I call you.  The chances are even that the man, when he
   is pursued, will return to this window and try to save himself that
   way; for it is by that way he came in and made a way ready for his
   flight.  You have a dangerous post.'
   "'What will be yours?' asked Fred.
   "'I shall spring into the room and knock him over for you.'
   "'Take my revolver,' said Fred, 'and I'll take your stick.'
   "'Thanks,' I said; 'You are a brave man.'
   "I accepted his offer.  I was going to be alone with the man in the
   room writing and was really thankful to have the weapon.
   "I left Fred, having posted him at the window (No. 5 on the plan),
   and, with the greatest precaution, went towards Monsieur Stangerson's
   apartment in the left wing of the chateau.  I found him with Daddy
   Jacques, who had faithfully obeyed my directions, confining himself