Evening star., 1921-08-21

| McCarty shrugged.
It's little worry you need to have
about Mr.; Terhune: tits only the brain
you're perfectly safe!"
| Dennis sniffed and pocketed the Of
tfending gloves, but made no reply and
in silence they started for the apart
ments of the criminologist.
An angular young man with the face
of a student opened the door to them
and smiled pleasantly
Mr.. Terhune told me that he was
expecting you and your friend. Mr.
arrangement Of his apparatus and he
said that you were both to go to tho
consulting room."
They found Terhune emerging from
the familiar screen in one corner Of
the great bare room which now was
furnished merely with row Of chairs
facing what appeared to be a motion
picture screen, and single chair set
forward and well at one side. like
that of a teacher before a class.
earlier. my dear McCarty. but there
will still be time for me to explain
our experiment this evening to you"
| Terhune shook hands in high good
humor.
| Il see by the papers that you and
Inspector Druet have followed the OBJ
vious course; I warned you against
| 1t. but l should have known how fu-
! tile my effort would be. Take my word
for 1t, McCarty, you win have to let
the valet Hill go within twenty-four
hours"
I'D not be surprised. sir" McCarty
| responded quietly, but there was a
| sudden twinkle in his eye.
| Dennis tugged surreptitiously at his
| sleeve.
What is it. moving pictures?" he
| asked in a rasping whisper.
Yes. of sort. Riordan." Terhune
himself answered with a smile. You
Will merely see q series of numbers
projected on the screen. but I will
explain them to you later. am using
the old association test. McCarty. but
| in connection with a new and i'm
| proved tonoscope called the vibrato-
| scope. Do you see this drum?'
He moved the screen aside as he
! spoke and displayed large cylindrical
case mounted upon a platform with
supports at either end and a scale
! like double foot rule projected
across but not touching its rounded
! side. which was perforated with
slanting rows of almost infinitesimal
| holes. Before 1t an upright brass
arm held a needle pointer tipped with
tiny fickering flame.
| Look at that. now" exclaimed
Dennis. impressed. And this vibrat-|
what you said. sir-what does it do?"
1T projects the vibration Of the
1
there. much in the manner of the
motion-p picture machine" responded
Terhune. ''The original tonoscope
merely registered the tonal quality.
showing by standardized scale
| whether it was sharp or fat, but with
this amp.ified vibratroscope the vocal
manifestations of emotion may be
measured down to an accuracy Of a
hundreth of a tone or even finer.
The vibrations of the voice. as you
see now while am speaking. cause
that little flame on the needle to
flicker. diminishing with the lowered
degrees of a single tone and rising
with its upward trend. Inside that
cylindrical case Is a large drum
which contains some $4,000 holes ar
ranged in rows so as to represent a
series Of tone shadings covering the
entire range of the human voice from
murmur to shrek. In a tonoscope
there are only $4,000 holes. which
form merely an octave. Do you fol-
low me?"
McCarty was studying the appa-
ratus closely. but Dennis nodded.
Yes. sir" he said somewhat un-
certainly. I'm quite a ways behind.
but misdoubt I'll catch up when 1
see 1t actually working on the screen.
And We don't have-to hold any little
bulbs nor wires nor anything?'
NO. merely to listen and watch. I
, shall not ask you nor McCarty to
take any more active part in tonight's
test"
But Just how does this work. Mr..
Terhune?" McCarty asked.
by the revolution of the, inner
drum. you see." explained the GRIM
inologist, Il set 1t in motion when
the test starts. If the speaker sounds
middle (Which in the original tono-
the line on the drum. which has 266
holes. will seem to remain stationary
while all the other rows are con-
tinuing to move; the line which
stands still points to that number on
the horizontal scale and is then prof.
the vfbratoscope, however, are diff
! ferently graded. In action the process
Is almost instantaneous. SO that sound
is seen at practically the same time
that it is heard. All, good evening.
Mr.. O'Rourke!"
He stepped from behind the screen
and drew its panel hastily across
after him SO that the earlier arrivals
were for the time being hidden from
the newcomer. and Dennis whispered
confidentially:
; Honest to God, Mac, did you un-
derstand one single word of all that
discourse? 1 did not, but small mat
; ter of that SO long as it's not my
! voice that contraption is taking ac-
! count of!
IL VIC Ou4y " "dICu lu0 SCIe0n ne
can start the show whenever he
wants What was 1t he said about
an association test? What kind of an
association is it? Are we all supposed
! to be members of the club?"
mo, you loon!" McCarty responded
with a low chuckle. He means the
! association of one word to another;
he mentions a word and you tell what
it brings up in your mind, what it
, means to you"
A moment later the dry. precise
heard and following upon his heels
/, came Inspector Druet.
j. Our gathering is complete now,"
/, Terhune announced. "McCarty, come
out from behind that screen. Gentle
men, you all know the Inspector q
; deputy, Mr.. McCarty. think. This is
a colleague Of his, Mr.. Riordan. Now,
If you will all be seated in that row
Of chairs facing the projection sheet
will explain the method Of this lit
tie test; you will find it almost child
ishly simple"
: Waverly turned with subdued guf-
Cutter, but the latter did not respond
and the gravity of his face remained
unbroken as he advanced and seated
himself at one end of the row of
: chairs. Waverly dropped into the
: next with O'Rourke beside him, then
Alexander. Inspector Druet and Nc
.. Carly. with Dennis bringing up at
the farther END. Bassett entered
!, only to efface himself silently behind
: chair at one side, drawing q sheaf
J of papers from his pocket.
You will see merely series of
numbers on the SCREEN" he began.