The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1897-08-08

tioning, either in regard to the senses, I'M
aglnatlon or reasoning.
To what extent does the mind get tired in
hot weather? It's SenSibility to fatigue was
measured at the laboratory by causing SUBJ
1ectS to continue repeating their dream i'm
ages of a thousand names of objects over
and over, without stopping until the brains
became so greatly fatigued they ceased to
repeat. Of twenty trials at a temperature
of Is degrees the average was about five
hours before the brains were completely
fatigued. When the temperature was 80 to
SO degrees the average length of time re-
CURED to completely fatigue the minds was
only one hour and forty-tWo minutes. The
two experiments were made on different
days when the minds had equal chances.
Other interesting experiments indicate to
what extent the muscles as we'll as the
mind are made more sensitive to fatigue
by very hot weather. A corresponding fin
ger of each subject was placed in an in
strument contriVed to tire it's muscles, as
it worked back and forth so as to compress
and release q spring. The instrument was
so regulated that the finger could be moved
about six hundred times in cadence with
a second pendulum before being completely
fatigued at a temperature of rs. At a tenn
p%erature of 90-93 the highest average num-
Der of movements which the same fingers
could make was 41O.
HEARING IMPAIRED.
Similarly it is shown how the extreme
high temperature of a very hot summer
day will dull the senses. To test relative
acuteness of hearing under varying temper
dluAllI CS5 u tulllhS AOIh was AOlO dL lII0
very farthest distance from the ear at
which it could be heard when the temper
allure was go degrees and had to be moved
IN average distance of Is per cent. nearer
before the vibrations made any impression
upon the hearing organ. Similar expert
ments were made to measure the effects of
temperature upon the other senses.
To learn to what extent practical brain
work is affected by high temperatures,
Professor Gates has made accurate meas
rementS of the relative lengths of time re-
CURED for the performances of a certain
mental task under varying conditions. He
selected twenty familiar problems in plane
geometry, which were reviewed and thor
oughly understood in every detail in 10 per
cent. less time when the temperature was IS
degrees than was equired to review the
same number of similar problems when the
temperature was raised to 81 degrees. This
indicates that an extremely hot day is IN
favorable to close mental study, such as
required for mathematical demonstrations,
and that 1t is proper that our schools should
be closed during summer months so long as
schoolrooms cannot be artiticially cooled.
Going still deeper, the effects of extreme
hot weather upon the chemistry of the body
ave been estimated by requiring subjects
to perform a task calculated to produce
artificial worriment or mental irritation.
The subjects were required to devote an
hour to the solution of geometrical prob
lens, taking each calculation into careful
consideration. During his solutions each
subject was asked q trivial and easily an
swered question every minute. The effect
of such a process at a temperature of go
degrees was the production of IS per cent.
more harmful phosphateS and indigotin
than were eXcreted at a temperature of rs
degrees. Such dangerous chemicals, Prof.
Gates says, increase under normal condi-
tons in proportion to the Worriment to
which the mind is subjected. This expert
ment, however, indicated that the same
amount of cause will create an increasing
amount of mental wOrriment as the tenn
perature rises above normal. Similarly it
roc HiCCnWnTn6 that tho mind in fpmnpF-
atures above normal, requires relative in
creaseS of time to recuperate from intense
fatigue. To ascertain this, subjects were
required to VISUALIZE until they could do
so no longer on account of fatigue. In a
temperature of rs degrees the mind recuper-
ated within an hour sufficiently to repeat
one hundred Installations slowly. AT a
temperature of 81 degrees, on the other
be made after the same lapse of time.
WHEN WE SUFFER MOST.
At what time on a summer day do we
usually feel hottest? The theory has been
that the body temperature rises to it's max
imum between 3 and s D. m, and then falls
to it's minimum between 2 and 6 in the
morning. Professor Gates made careful
observations of a street-car conductor dur
ing both his day and night periods of work.
1t was discovered that the above was true
when the conductor worked during the day
and slept at night, but that the order was
reversed when he worked at night and slept
in the day. This indicated to the professor
that the rise and fall of the body's temper
ature is the result of waking activity rather
than of sunlight, as has been the theory
heretofore.
When asked to describe and explain dam
gerous effects of extremely hot days. such
as we are now having, Professor Gates
said: Sudden hot weather, reaching a tenn
p~erature of from Sc to % degrees Fahren-
heit, causes the breathing and the pulse To
become abnOrmally rapid because the blood
is in need of more oxygen and the brain
requires more blood to stimulate thought.
Increased fatigue in summer is partly due
to wear and tear on the nerves which are
active in producing perspiration and in pre-
venting the of too much fuel.
Such wear and tear is very exhausting.
But there are greater dangers than these.
There is a fraction of a second between ev-
cry heart beat when that organ is at rest.
l have found by aid Of an instrument which
indicates heart beats in waved lines that
when the temperature of the air Is 90 the
amount of this rest is about half of what
il is when the temperature is Is. Thus con-
tinued hot weather tends to produce heart
failure and nervous prostration- Most
heart Diseases result from the fact that
the heart gets insufficient rest. What is
commonly called 'nervousness,-character-
lied by trembling Of the hands-is increased
by hot weather. as indicated by experiments
with an instrument which automatically