Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1889-06-02
MEASURING PAIN,
Recording the Speed Of a Rheumatic
Twinge-A Remarkable Instrument.
Amarfcan ADalvex

Recording the Speed Of a Rheumatic
Twinge-A Remarkable Instrument.
American Analyst.1
The University of Pennsylvania is the
pioneer in introducing the mind measuring
system into America. Prof. Cattell recently
brought with him from Germany some
quite remarkable instruments, principally
of his own invention. which are to be here
after employed in demonstrating his psyche
logical lectures. They perform tasks which
materialists have secuted as impossibilities,
and strongly tend to prove that psychology,
despite all that has been said to the con-
trary, is an exact science.
One of these instruments will calculate to
nicely the travelling speed of an impression.
A chronoscope and a voltaic battery are the
principal agents in the solution Of this in
tricate problem. By their means registra-
tion 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 act By process
of subtraction the time is discovered which
passes between the moment at which the i'm
preston reaches consciousness, and the
moment when the subject knows that he per-
ceives. In this manner mans rapidity of
perception-his ability to see, taste. smell.
hear or feel-may be accurately determined.
For the measurement of sound the subject
forms q circuit by applying his hands to the
two poles of the battery On hearing a
specified noise he instantly breaks the cir
cult Immediately the hand of the chrono-
scope stops. short, indicating in thousandths
of second the time that has elapsed be-
fvuo fho aof 4Lo
breaking of the circuit
On this basis mans perceptive power is
calculated. By analogous means the COM
parative swiftness of sight is measured.
Prof. Cattell has ascertained, for instance
that one-tenth of second sufices for him
to perceive color one-eighth of a second
is necessary for the perception of a letter
and one-seventh of a second for a word
The strength of persons memory is deter
mined by complicated machine which
presents to the eye at intervals of second.
flashes of light of varying degrees of intea-
sity. The more subtle is mans power of
recognition, the more readily he distin-
guishes one light spot from another, and
the longer he retains its impressions. In this
way the minds concentration and reten.
tiveness are measured in fractions of a Sec
ond. By means of the gravity chronometer
the comparative easeo difficulty with which
letters or words may be perceived is demon.
strated. In a sliding screen moved
by electricity slit five inches wide is in
serted behind whichan object is exposed to
view for an infnitesimal space of time. In
a series of experiments with the letters of
the alphabet the time of exposure was one
thousandth of a second. Out of 27O trials
W was seen 241 times, while E appeared
seen but 60 times. OF other capital letters
q, N, d and b ranked next in succession
after in the quickness with which they were
perceived, while V, F, q and j were OBJ.
served only with great difficulty. Of the
small letters is the most easily recognized
and least easily, the former being Der.
ceived three times as often as the latter. If
the several colors are exposed to view in
like manner for fraction of a second orange
and yellow will be clearly perceived. Blue.
red and green follow in the order named
violet being the least easily recognized and
requiring two or three times as long ex-
posure as the bright colors. This device is
Of great value4n measuring the range or
of the mind.