Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1913-02-13

we know as light. Light waves vary
in length between one thirty-three-
thousand-fO -hundredth and one six
ty- tive-thousandt of an inch. the first
being extreme red and the second ex
treme violet Rays of white light
have Il length of one fOrty-fve-thou-
sandth of an inch. The sun IS a great
mass of white hot matter. 1t is the at
mosphere that enables us TO see light,
and outside of orr atmosphere it is alb
solute darkness. as dark as the interior
of Mammoth cave. In an arc lamp It
is the white hot particles of carbon
floating between the two electrodes
that produce light. In the incandes-
cent lamp it is the hairpin filament in
side the glass globe that. when heated
by electricity. gives off light waves.
In gas and oil lamps light is produced
by the heated particles OF carbon in the
flames above the wick or mantle.
The eye can stand without firing
bTilliance of about five candle power
to the square inch of surface. The or
dIuary candle flame gives only two OF
three candle power to the square inch,
while the sun at zenith gives 100000.
The are light ranks next TO sunlight,
with 10000 candle power an inch. and
the best tungsten tilament incandes-
cents give 1000 candle power. This
means that if the sun could be chang
ed into Il ball of tungsten it would
throw Off only 1000 candle power of
light from every square inch of its
surface. when the world would be
practically dark and we should freeze
to death in 4 week.
The prism shows that white light Is
composed OF a happy blend of all col
ors of the spectrum. The sun gives
the only pure white light. with the arc
lamps close second and the metal
filament incandescents taking third
place. Sky light. such as comes from
the north on a clear day. is blush
white. Gas nantes give greenish
light. open fame yellow light and kero-
sene orange light.
BY the laws of evolution the human
eye has become accustomed to sun
light. or sky light. coming obliquely
from above. and our eyes resent light
coming from any other source Snow
blindness. distress from white sand or
water, Is the result of violating this
rule. The upper eyelid is adapted to
shade the eye from a strong light
from above. The lower lid cannot per
form this Office. so when a strong light
Is reflected up into the eyes it blinds
us.
The z ray has proved beyond doubt
that there are light rays which move
too fast for human eyes to register.
This light penetrates books. wood. pa
per and even human flesh. With the
microscope to assist our eyes we can
See the bones in our arm without both
ering to remove coat or shirt. But a
man with Y ray eyes would be sadly
Handicapped in this world. for he
could see nothing but solids. such as
earths and metals. and would be IN
able to see board fence at all. Be
| Sond doubt there is light so bright
that the eyes cannot see it, and to us
all is darkness beyond what our eyes
will register.
Light rays themselves are invisible.
Nv Hcu IuSS move tuTOuSH Tue etucE
alone our eyes cannot see them. conse
| huently all is total darkness. But
when they meet with the resistance of
bur atmosphere. producing heat. they
register on the retina and-behold. we
kan see. AS the atmosphere thins
tapidly as we go upward. so IN pro
portion the air resistance diminishes
lind consequently the heat of the sun
seems to grow less. This explains
why the tops of high mountains are
always covered with snow.
Many wonderful discoveries have
been recorded in the illuminating field
1 Of late. and ID is safe 10 say thai this
| branch Of science affords one Of the
! greatest fields for research and inven
,tion. Each year our artihcial illuTi
laants are improved, but they are fal
from being perfect. Not until the Sc
icret Of the firahy is read and light II
produced without heat will our even
tnr lamps be rerfect-Chicago Record
Herald