Suddenly came a wild scream. It was such a scream as I had never
heard before in my life. It came as though a dagger had been thrust into
the heart of Mrs. Popper. The lights flashed up as Kennedy turned the
switch.
A man was lying flat on the floor--it was Inspector O'Connor. He had
succeeded in slipping noiselessly, like a snake, below the curtain
into the cabinet. Craig had told him to look out for wires or threads
stretched from Mrs. Popper's clothing to the bulging curtain of the
cabinet. Imagine his surprise when he saw that she had simply freed
her foot from the shoe, which I was carefully holding down, and with a
backward movement of the leg was reaching out into the cabinet behind
her chair and was doing the rapping with her toes.
Lying on the floor he had grasped her foot and caught her heel with a
firm hand. She had responded with a wild yell that showed she knew she
was trapped. Her secret was out.
Hysterically Mrs. Popper began to upbraid the inspector as he rose to
his feet, but Farrington quickly interposed.
“Something was working against us to-night, gentlemen. Yet you demanded
results. And when the spirits will not come, what is she to do? She
forgets herself in her trance; she produces, herself, the things that
you all could see supernaturally if you were in sympathy.”
The mere sound of Farrington's voice seemed to rouse in me all the
animosity of my nature. I felt that a man who could trump up an excuse
like that when a person was caught with the goods was capable of almost
anything.
“Enough of this fake seance,” exclaimed Craig. “I have let it go
on merely for the purpose of opening the eyes of a certain deluded
gentleman in this room. Now, if you will all be seated I shall have
something to say that will finally establish whether Mary Vandam was the
victim of accident, suicide, or murder.”
With hearts beating rapidly we sat in silence.
Craig took the beakers and test-tubes from the shelf behind the curtain
and placed them on the little deal table that had been so merrily
dancing about the room.
“The increasing frequency with which tales of murder by poison appear
in the newspapers,” he began formally, “is proof of how rapidly this new
civilisation of ours is taking on the aspects of the older civilisations
across the seas. Human life is cheap in this country; but the ways
in which human life has been taken among us have usually been direct,
simple, aboveboard, in keeping with our democratic and pioneer
traditions. The pistol and the bowie-knife for the individual, the rope
and the torch for the mob, have been the usual instruments of sudden
death. But when we begin to use poisons most artfully compounded
in order to hasten an expected bequest and remove obstacles in its
way--well, we are practising an art that calls up all the memories of
sixteenth century Italy.
“In this beaker,” he continued, “I have some of the contents of the
stomach of the unfortunate woman. The coroner's physician has found that
they show traces of morphine. Was the morphine in such quantities as to
be fatal? Without doubt. But equally without doubt analysis could not
discover and prove it in the face of one inconsistency. The usual test
which shows morphine poisoning failed in this case. The pupils of her
eyes were not symmetrically contracted. In fact they were normal.
“Now, the murderer must have known of this test. This clever criminal
also knew that to be successful in the use of this drug where others had
failed, the drug must be skilfully mixed with something else. In that
first box of capsules there were six. The druggist compounded them
correctly according to the prescription. But between the time when they
came into the house from the druggist's and the time when she took the
first capsule, that night, someone who had access to the house emptied
one capsule of its harmless contents and refilled it with a deadly dose
of morphine--a white powder which looks just like the powder already in
the capsules.
“Why, then, the normal pupils of the eyes? Simply because the criminal
put a little atropine, or belladonna, with the morphine. My tests show
absolutely the presence of atropine, Dr. Hanson,” said Craig, bowing to
the physician.
“The best evidence, however, is yet to come. A second box of six
capsules, all intact, was discovered yesterday in the possession of
Henry Vandam. I have analysed the capsules. One contains no quinine at
all--it is all morphine and atropine. It is, without doubt, precisely
similar to the capsule which killed Mrs. Vandam. Another night or so,
and Henry Vandam would have died the same death.”
The old man groaned. Two such exposures had shaken him. He looked from
one of us to another as if not knowing in whom he could trust. But
Kennedy hurried on to his next point.
“Who was it that gave the prescription to Mrs. Vandam originally? She is
dead and cannot tell. The others won't tell, for the person who gave her
that prescription was the person who later substituted the fatal capsule
in place of the harmless. The original prescription is here. I have been
able to discover from it nothing at all by examining the handwriting.
Nor does the texture of the paper indicate anything to me. But the
ink--ah, the ink.
“Most inks seem very similar, I suppose, but to a person who has made a
study of the chemical composition of ink they are very different. Ink
is composed of iron tannate, which on exposure to air gives the black of
writing. The original pigment--say blue or blue-black ink--is placed
in the ink, to make the writing visible at first, and gradually fades,
giving place to the black of the tannate which is formed. The dyestuffs
employed in the commercial inks of to-day vary in colour from pale
greenish blue to indigo and deep violet. No two give identical
reactions--at all events not when mixed with the iron tannate to form
the pigment in writing.
“It is owing to the difference in these provisional colouring matters
that it is possible to distinguish between writing written with
different kinds of ink. I was able easily to obtain samples of the
inks used by the Vandams, by Mrs. Popper, by Mr. Farrington, and by the
druggist. I have compared the writing of the original prescription with
a colour scale of my own construction, and I have made chemical
tests. The druggist's ink conforms exactly to the writing on the two
pill-boxes, but not to the prescription. One of the other three inks
conforms by test absolutely to the ink in that prescription signed 'Dr.
C. W. H.' as a blind. In a moment my chain of evidence against the owner
of that bottle of ink will be complete.”
I could not help but think of the two pendulums on the shelf behind
the curtain, but Craig said nothing for a moment to indicate that he
referred to that apparatus. We sat dazed. Farrington seemed nervous
and ill at ease. Mrs. Popper, who had not recovered from the hysterical
condition of her exposure, with difficulty controlled her emotion.
Vandam was crushed.
“I have not only arranged this laboratory so as to reproduce Mrs.
Popper's seance-room,” began Craig afresh, “but I have had the cabinet
placed in relatively the same position a similar cabinet occupies in Mr.
Vandam's private seance-room in the Vandam mansion.
“One night, Mr. Jameson and myself were visiting Mr. Vandam. At
precisely twelve-thirty we heard most unaccountable rappings from that
cabinet. I particularly noted the position of the cabinet. Back of
it ran a hallway. That is duplicated here. Back of this cabinet is a
hallway. I had heard of these rappings before we went, but was afraid
that it would be impossible for me to catch the ghost red handed. There
is a limit to what you can do the first time you enter a man's house,
and, besides, that was no time to arouse suspicion in the mind of
anyone. But science has a way out of every dilemma. I determined to
learn something of these rappings.”
Craig paused and glanced first at Farrington, then at Mrs. Popper, and
then at Mr. Vandam.
“Mr. Jameson,” he resumed, “will escort the doctor, the inspector, Mr.
Farrington, Mrs. Popper, and Mr. Vandam into my imitation hall of the
Vandam mansion. I want each of you in turn to tiptoe up that hall to a
spot indicated on the wall, back of the cabinet, and strike that spot
several sharp blows with your knuckles.”
I did as Craig instructed tiptoeing up myself first so that they could
not mistake his meaning. The rest followed separately, and after a
moment we returned silently in suppressed excitement to the room.
Craig was still standing by the table, but now the pendulums with the
magnets and needles and the drums worked by clockwork were before him.
“Another person outside the Vandam family had a key to the Vandam
mansion,” he began gravely. “That person, by the way, was the one who
waited, night by night, until Mrs. Vandam took the fatal capsule,
and then when she had taken it apprised the old man of the fact and
strengthened an already blind faith in the shadow world.”
You could have heard a pin drop. In fact you could almost have felt it
drop.
“That other person who, unobserved, had free access to the house,” he
continued in the breathless stillness, “is in this room now.”
He was looking at O'Connor as if for corroboration. O'Connor nodded.
“Information derived from the butler,” he muttered.
“I did not know this until yesterday,” Kennedy continued, “but I
suspected that something of the sort existed when I was first told by
Dr. Hanson of the rappings. I determined to hear those rappings, and
make a record of them. So, the night Mr. Jameson and I visited Mr.
Vandam, I carried this little instrument with me.”
Almost lovingly he touched the pendulums on the table. They were now
at rest and kept so by means of a lever that prevented all vibration
whatever.
“See, I release this lever--now, let no one in the room move. Watch
the needles on the paper as the clockwork revolves the drums. I take a
step--ever so lightly. The pendulums vibrate, and the needles trace a
broken line on the paper on each drum. I stop; the lines are practically
straight. I take another step and another, ever so lightly. See the
delicate pendulums vibrate? See, the lines they trace are jagged lines.”
He stripped the paper off the drums and laid it flat on the table before
him, with two other similar pieces of paper.
“Just before the time of the rapping I placed this instrument in the
corner of the Vandam cabinet, just as I placed it in this cabinet after
Mr. Jameson conducted you from the room. In neither case were suspicions
aroused. Everything in both cases was perfectly normal--I mean the
'ghost' was in ignorance of the presence, if not the very existence, of
this instrument.
“This is an improved seismograph,” he explained, “one after a very
recent model by Prince Galitzin of the Imperial Academy of St.
Petersburg. The seismograph, as you know, was devised to register
earthquakes at a distance. This one not only measures the size of
a distant earthquake, but the actual direction from which the
earth-tremors come. That is why there are two pendulums and two drums.
“The magnetic arrangement is to cut short the vibrations set up in the
pendulums, to prevent them from continuing to vibrate after the first
shock. Thus they are ready in an instant to record another tremor. Other
seismographs continue to vibrate for a long time as a result of one
tremor only. Besides, they give little indication of the direction from
which the tremors come.
“I think you must all appreciate that your tiptoeing up the hall must
cause a far greater disturbance in this delicate seismograph than even
a very severe earthquake thousands of miles away, which it was built to
record.”
He paused and examined the papers sharply.
“This is the record made by the 'ghost's' walk the other night,” he
said, holding up two of them in his left hand. “Here on the table, on
two other longer sheets, I have records of the vibrations set up by
those in this room walking to-night.
“Here is Mr. Jameson's--his is not a bit like the ghost's. Nor is Mr.
Vandam's. Least of all are Dr. Hanson's and Inspector O'Connor's, for
they are heavy men.
“Now here is Mr. Farrington's”--he bent down closely, “he is a light
man, and the ghost was light.”
Craig was playing with his victim like a cat with a mouse.
Suddenly I felt something brush by me, and with a swish of air and of
garments I saw Mrs. Popper fling herself wildly at the table that bore
the incriminating records. In another instant Farrington was on his feet
and had made a wild leap in the same direction.
It was done so quickly that I must have acted first and thought
afterward. I found myself in the midst of a melee with my hand at
his throat and his at mine. O'Connor with a jiu-jitsu movement bent
Farrington's other arm until he released me with a cry of pain.
In front of me I saw Craig grasping Mrs. Popper's wrists as in a vise.
She was glaring at him like a tigress.
“Do you suppose for a moment that that toy is going to convince the
world that Henry Vandam has been deceived and that the spirit which
visited him was a fraud? Is that why you have lured me here under false
pretences, to play on my feelings, to insult me, to take advantage of a
lone, defenceless woman, surrounded by hostile men? Shame on you,” she
added contemptuously. “You call yourself a gentleman, but I call you a
coward.”
Kennedy, always calm and collected, ignored the tirade. His voice was
as cold as steel as he said: “It would do little good, Mrs. Popper, to
destroy this one link in the chain I have forged. The other links are
too heavy for you. Don't forget the evidence of the ink. It was your
ink. Don't forget that Henry Vandam will not any longer conceal that he
has altered his will in favour of you. To-night he goes from here to his
lawyer's to draw up a new will altogether. Don't forget that you have
caused the Vandams separately to have the prescription filled, and that
you are now caught in the act of a double murder. Don't forget that you
had access to the Vandam mansion, that you substituted the deadly for
the harmless capsules. Don't forget that your rappings announced the
death of one of your victims and urged the other, a cruelly wronged and
credulous old man, to leave millions to you who had deceived and would
have killed him.
“No, the record of the ghost on the seismograph was not Mr.
Farrington's, as I implied at the moment when you so kindly furnished
this additional proof of your guilt by trying to destroy the evidence.
The ghost was you, Mrs. Popper, and you are at liberty to examine the
markings as minutely as you please, but you must not destroy them. You
are an astute criminal, Mrs. Popper, but to-night you are under arrest
for the murder of Mary Vandam and the attempted murder of Henry Vandam.”