, 1889-08-22
4LmosT THE PsilLosoPHER'8 SCALES
EteniarkabIe Instruments Used by the Mod
eru fsvg.I:iO-Ists.

! fG2markabIe Instruments Used by the Mod.
| eru Psychologists.
! Robin Goodfcllow" might boast that
! he could put 4 Girdlc round the earth in
forty minutes, but nlcasrtl psychologists
are learning TO accomplish far nlore re-
markable things. In the world of mat
ter they are of little worth, but they have
gotten hold of the minds leading strings,
and have coutrivcd so .ingeniously that
''all thoughts, all passions, all delights
have become re,iuCiJle to mathematical
formula. Not only have they learned
to express the poets dream in Prosaic
millimetrcs, and affairs Of the heart in
cold, unfeeiing dpciinais,- but the iHten-
sity of q stroke o. tumbago and the rate
OF speed Of dysr-ptic twinge they now
calculate with numerical cXactness.
1t is an actual fact that psychologists
will soon have as complete insight into
.hc operations Of the mind as have ply
sicians into the functions of the body.
| The University of Pennsylvania is the
pioneer in introducing the mind measur-
ing system into America. Professor Cat
tell brought with him from Germany
some quite remarkable instruments,
principally of his own invention, which
nre employed in demonstrating his psy-
Geological lectures. They perform tasks
Which nIaterialists have secuted as i'm
possibilities, and strongly tend to prove
that psychology, despite all that has been
said to the contrary, is an exact science.
One of these Instruments will caicu-
late to q nicely the travelling speed of an
impression. a chronoscope and vol
taic battery are the principal agents in
the solution Of this intricate problem.
By their means registration is made Of
the exact time that elapses between the
occurrence of an act and the sign given
by the subject operated>upon that he has
perceived the ac3. BY process of sub
traction the time is discovered which
passes between the moment at which
| the impression reaches consciousness
and the moment when the subject knows
he pcrceivcs. In this manner mans
rapidity OF perception-his ability to see,
taste, smell, hear Or feel-may be accu-
rately determined. s@
For the measurements of sound the sub
ject forms a circuit by applying his hands
to the two poles of the battery On hear
ing specified noise he instantly breaks
the circuit, Immediately the hand of
the chronoscope stops short. indicating
i'll thOusandths OF q second the time that
| has elapsed between the occurrence of
the sound and the breaking of the cir
| cult. On this basis mans perceptiye
power is calculated.
| BY analogous means the comparative
nfs Iof1t iG
| sor Cattell has ascertained, for instance.
| that one-tenth of second suffices for
him to perceive color, oce-eiShth of 4
second is necessary for the perception of
4 letter, and one-seventh of second for
a word. sa.a
The strength of a persons memory is
determined by 4 complicated machine
which presents to the eye at intervals of
Il second flashes of light of varying de-
grees of intensity. The more subtle is
mans power of recognition the more
readily he distinguishes one light spot
from another, and the longer he retains
his impressions. In this way the minds
concentration and retentiveness are
measured in fractions of a second
By means of the gravity chronometer
l4iS SSloC Will
which letters or words may be perceived
is demonstrated. In 4 sliding screen
moved by electricity a slit five inches
wide is inserted, behind which an object
is exposed to view for an infnitessimI
space of time.
In series of experiments with the
letters of the alphabet the time of expos
ure was one-thousandth of q second.
That of 270 trials w was seen 241 times,
while E appeared seen but 63 times. OF
other capital letters z, II, D and II
ranked next in succession after in the
quickness with which they were per-
ceiyed, while Y, +, U and j were OBJ
served only with great difficulty. OF
the small letters I'd" is the most easily
recognized, and IS" least easily, the for
mer being perceived three times as often
as the latter.
If the several colors are exposed to
view in like manner for a fraction of a
second orange and yellow will be most
clearly perceived Blue, red and green
follow in the order named, violet being
the least easily recognized and requiring
two or three times IS long exposure as
the bright color5. This device serves to
measure the range OR complexity of the
mind.-Philadelphia Record.