The Daily times. [volume] (Richmond, Va.) 1886-1889, 1889-06-16
Al MOST T7E P!IH.o3oPHER's ecALes
Kcu.qrisablc Instruments Used by the Mod
crn Psychologists.

Kcn.qrlsablc Instruments Used 10y the Mod
crn Psychologists.
robin Go0dfclow' might boast that
he could put girdle round ihc earth IN
forty minutes, but modern psychologists
are learning 10 accomplish iar more re-
markable things. III .he world/,f mat
ter they are of iitileworth. but " have
gotten hold of thcminds leading strings.
and nave contri,cd SO ineeaiou-iy thai
"ail thoughts, AID passions. all delights
have become rcducihle 90 mathematical
formula. Not only have they learned
TO express the poet s. dream ia rroaic
millimcrres. and affairs of the heart 90
cold. unfcclmg dccimals, hut the intcn-
silv of "a stroke of mmha-o and thc rate
of speed Of 70 dyspcpiic tUinec lhey no"
calculate with numerical cNacincs-.
ltisan actual fact THAT psychologists
will soon have as complete insight into
tine 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 mcasnr
Inc system into America. Professor Cat.
tell brought with him from Germany
some quite remarkable Instruments
principally Of his own invention which
are employed IN demonstrating hispsy-
GEOLOGICAL lectures. They perform tasks
which materialiats have secuted as im.
possibilities and strongly tend 20 prove
that psychology, despite all that has been
said 10 the contrary. is ar exact science
One Of these Instruments will cllcu
late 10 a nicely the travelling speed oi ah
IMPRESSION A cironoscope and vol
tale battery are the principal agents no
the solution Of this intricate problem.
Bv their means registration is made Of
The exact time that oiapscs between the
occurrence vf am act and the sign given
by the subject operated upon that he has
perceived the act By a process Of sub
traction the time is discovered which
passes between the moment 40 which
the impression reaches consciousness
and the moment when the subject knows
he pcrceivcs. In this manner q mans
rapidity Of pcrccption-his ability tosee,
taste. smell. hear or fcei-may be accu-
rately determined.
For the measurement of sound the sub
iect forms circuit by applying his hands
10 the two poles Of the hattcry. On hear
inc q specified noise he instantly breaks
the circuit. immediately the hand of
the chronoscopc stops short. indicating
in thousandtlis Of q second tho time that
has elapsed between the occurrence OF
the sound and the breaking of the cir
cult. On this basis mans perccptiye
power t. calculated
By analogous means the comparative
swifness OF sight is measured. Profcs
sor Cattell has ascerained. for instance.
that one-tcnth Of second su1icos fol
him 10 perceive a color, occ-cighth Of a
second is necessary for the perception OF
a letter. and onc-scventh cf "a second for
a word,
The strength OF a persons memory j.
determined by complicated machine
which presents 70 the eye az intervals of
a second flashes Of light IF varying de-
grees of intensity. The more subtle Is q
mans power of recognition the more
readily hc distinguishes one light spot
from another. and the longer hc retains
his impressions. In this way the minds
concentration and rctentiycncss are
measured in fractions Of a second.
BY means Of The gravity chfoaomctei
the comparative ease or difficulty with
which letters or words may be perceived
is demonstrated. In sliding screen
moved by electricity slit five inche.
wide is inserted. behind which an object
is exposersto view for an ininitessimai
space Of lime.
In a series 81 experiments with the
letters Of the alphabet the time OF expos
ure was one-ihousandth Of second.
That Of 2iu trials u was seen 2il times.
while l. appeared seen bet c. times. OIL
other capital letters Z, N. u and II
ranked next In succession after in the
quickncss with which thcy were per.
ceiyed. while Y. +, U and were OBJ