Evening star., 1934-10-18
BY THOMAS r. HENRY.

Much Of the nerve strain Of modern
life Is due to working in little more
than q five-hundredth part Of the
light nature intended for o human
being, DR.. M. Luckiesh Of the Light
ing Research Laboratory of the Gen.
eral Electric Co. told the Optical So
ciety Of America at It's annual meet
ing at the Bureau Of Standards to-
day.
DR.. Luckiesh is in Washington as
a consultant on lighting arrange
ments at the White House which, he
said, have been so bad as to consti-
tute heavy additional strain on the
Presidents and their office forces.
The new executive offices will be given
as nearly daylight conditions as pos
sible.
He revealed to the Optical Society
measurements which show that See
ing" is a function of the whole body
and not of the eyes alone. It is ac-
companied by nervous tensions that
probably leave no part of the system
unaffected. Over period Of IL years
more than a million measurements
have been made of the reactions at
tendant upon vision. As illumination
is decreased below that of outdoor
sunlight, for example, the heart beat
slows down until at one foot candle
or the amount Of light given by an
ordinary candle a foot away-it Is
eight beats q minute slower than
normal. q.
Nerve Tension Measured.
Subjects were studied while reading
ordinary book type at various illu-
limitations from 1000 to one foot
candles, the tips of their fingers be-
ing kept on buttons which recorded
nervous tension. Ache Illumination
was decreased to unconscious pressure
increased from 4. ITO Sc grams. Similar
studies were made of the tension of
the eye muscles which move the eyes.
but have nothing to do directly with
vision itself. 1t was three times
greater at one foot candle than at 100.
Ordinary outdoor illumination at
noon Of bright Summer day in the
open, DIR. Luckiesh said, is about
10,000-foot candles. In the shade
of tree or building 1t Is about 1000.
Near window indoors it is about 500.
Yet, he pointed out, few feet back
from the window the illumination
dropped to a little more than two
foot candles without artificial illumi.
nation and this is about what is
provided in the ordinary house or
office by illumination at night. It Is
probable, he said, that greater part
of the civilized worlds work is done
at about two-foot candles, whereas
the human being developed as a see
ing machine over millions of years
in an Illumination about 500 times as
great. The experiments show clearly,
he says, that during the few thousand
years the race has been working in
doors there has been no adaptation
to dim light.
Although there is minimum of
physical effort, DR.. Luckiesh said, the
clerk who sits at desk all day is
just about as tired as the woodchopper
or ditch-digger at quitting time. Since
fatigue is supposed to be due to the
liberation within the body Of GER
tain toxins by muscular exertion,
which must be removed by rest or
slepe. the tired feeling" Of the office
sleep, the tired feeling" of the ONCE
worker has been a puzzle to physi-
ologists. Actually, the job of merely
seeing" in the dim light Of the office,
DIR. Luckiesh said, may involve about
as much exertion, and more nervous
strain, than the woodchopper's use
of his muscles. The office worker
doesn't even know he is working for
he seems to be seeing without effort,
and fatigue creeps upon him.
May Cause Heart Malady.
The strain of seeing on the heart,
DR.. Luckiesh believes, is largely re-
sponsible for the enormous increase
of deaths from heart failure which has
puzzled the medical profession. This
increase during the past half century,
he says has been fairly well correlated
with the number Of indoors workers
in Offices and factories. During this
period the actual lighting has i'm
proved very little, in spite of gas
and electricity, and the worker gets
hardly better illumination than was
had by his great grandmother who
read and sewed by candle-light. The
candle could be brought very close to
the task at hand so that the full
benefit of its light was obtained. The
electric light is far away.
Optico-physiological experiments in
the past, DR.. Luckiesh said have been
concerned largely with finding how
little light was absolutely necessary
for vision without any consideration
of the whole body as seeing ma
chine" developed through millions of
years of evolution under totally differ
ent condition. Optical science now
has turned to the determination of
how man can see best.
He compares the human seeing
machine" with an automobile, in
tended to run most Of the time in
high, but with low gear for starting
and for emergencies. Man can see
with very little light, this ability be-
ing akin to the low gear. The trouble
is that he runs the machine in low
gear most of the time and soon tears
1t to pieces.
Light Needs Compared.
His experiments have demonstrated
some striking differences in the
amount of illumination. required for
different tasks. If it is not supplied
it must be made up for by largely
unconscious physical exertion. Thus
ordinary sewing requires about 1000
times as much light as reading ordi-
nary newspaper type. Reading the
stock quotations in a newspaper is
an immensely harder job" than
reading the ordinary news matter.
The stenographer who tries to read
her shorthand notes must "see" as
well as the engineer setting a slide
rule. If the light Is not provided 1t
must be compensated for by the